CePd2Al8 – A ferromagnetic Kondo lattice with new type of crystal structure

Accepted Manuscript CePd2Al8 – A ferromagnetic Kondo lattice with new type of crystal structure Anna Tursina, Emma Khamitcaeva, Daniel Gnida, Dariusz Kaczorowski PII:

S0925-8388(17)33443-6

DOI:

10.1016/j.jallcom.2017.10.031

Reference:

JALCOM 43428

To appear in:

Journal of Alloys and Compounds

Received Date: 24 July 2017 Revised Date:

23 September 2017

Accepted Date: 5 October 2017

Please cite this article as: A. Tursina, E. Khamitcaeva, D. Gnida, D. Kaczorowski, CePd2Al8 – A ferromagnetic Kondo lattice with new type of crystal structure, Journal of Alloys and Compounds (2017), doi: 10.1016/j.jallcom.2017.10.031. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT

CePd2Al8 – a ferromagnetic Kondo lattice with new type of crystal structure Anna Tursina1, Emma Khamitcaeva1, Daniel Gnida2 and Dariusz Kaczorowski2* 1

Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia Institute of Low Temperature and Structure Research, Polish Academy of Sciences,

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2

Abstract

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P.O. Box 1410, 50-950 Wrocław, Poland

The novel cerium aluminide CePd2Al8 was investigated by means of single crystal X-ray and low-temperature magnetic,

electrical transport and heat

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diffraction

capacity

measurements. The compound is found to crystallize with a monoclinic structure of its own type with a single crystallographic position for Ce atoms in the unit cell. Due to magnetic moments carried on Ce3+ ions, it exhibits Curie-Weiss paramagnetic behavior and long-range ferromagnetic ordering below TC = 9.5 K. In the entire temperature range studied, the physical

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properties of CePd2Al8 are influenced by Kondo interactions with an energy scale close to TC.

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Keywords: cerium intermetallics; crystal structure; magnetic properties; Kondo effect

Prof. Dr. Dariusz Kaczorowski

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*Corresponding author:

Tel.: +48 71 34 350 21; Fax: +48 71 34 410 19 E–mail: [email protected]

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ACCEPTED MANUSCRIPT 1. Introduction All the hitherto described ternaries forming in the Ce-Pd-Al system possess a relatively low Ce content being limited to 33.33 atom %, observed in CePdAl [1]. In the course of our on-going reinvestigation of this phase diagram, a novel ternary aluminide, viz. CePd2Al8, was discovered to exist. The compound is also poor in Ce atoms however very rich

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regarding Al content. Numerous aluminides and gallides RET2M8 (RE = rare earth, T = Co, Fe, Ru; M = Al, Ga) have been reported in the literature, and all of them crystallize with the orthorhombic crystal structure of the CeFe2Al8-type [2]. On the other hand, the only indides RET2M8 (M =

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In) known so far are EuRh2In8 [3] and SrRh2In8 [4]. Both compounds are also isostructural with CeFe2Al8 [3,4]. Interestingly, CePd2Al8 is the RET2M8 compound that adopts a different crystal structure of its own type.

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In this paper we describe the crystal structure of CePd2Al8 as well as its physical properties, studied in wide ranges of temperature and magnetic field strength. Remarkably, The compound was found a ferromagnetic Kondo lattice, a novel member of the family of Cebearing Kondo ferromagnets. It is worth recalling that the latter group comprises quite a small number of representatives, in contrast to the mostly observed Kondo antiferromagnets. Rare

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examples of the recently studied ferromagnetic Kondo systems are CeRuPO [5], Ce3RhSi3 [6], CePd2P2 [7], and Ce(Cu,Al,Si) [8], which behave at low temperatures in a similar manner as the Kondo lattice ferromagnets reported before, like CeNiSb [9], CePd2Ga3 [10] or CeAgSb2

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[11].

2. Experimental details

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Polycrystalline sample of CePd2Al8 was prepared by arc-melting stoichiometric

amount of the elemental constituents (purity: Ce 99.85 mass %, Pd 99.99 mass %, and Al 99.999 mass %) in an Edmund Bühler MAM-1 compact arc-furnace on a water-cooled copper hearth under argon atmosphere. Subsequently, the ingot was sealed in evacuated quartz tube and annealed at 1070 K for 30 days. The heat treatment was finished with quenching the sample in cold water. Single crystal suitable for X-ray diffraction (XRD) data collection was found on surface of the annealed sample. The XRD intensities were measured on a CAD4 Enraf Nonius diffractometer (Ag Kα radiation, ω/θ-scan). An empirical absorption correction was applied on the basis of Ψ-scan data [12]. All the relevant crystallographic data and experimental 2

ACCEPTED MANUSCRIPT details on the data collection are gathered in Table 1. The structure was solved using direct methods and refined by full-matrix least-square method in anisotropic approximation using SHELX-97 program [13]. Site occupancy refinement indicated full occupancies for all the crystallographic sites. Final refinement of the crystal structure converged to the residuals given in Table 1. The positional parameters, standardized with the program STRUCTURE

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TYDI [14] and selected interatomic distances are listed in Tables 2 and 3, respectively. Purity of the polycrystalline sample was tested by powder XRD and energy-dispersive X-ray spectroscopy (EDX). The powder XRD data were collected at room temperature with a Stoe Stadi-P transmission diffractometer (Cu Kα1 radiation), equipped with a curved Ge(111)

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primary beam monochromator and a linear position-sensitive detector. No impurities were detected on the XRD pattern, whereas EDX revealed some traces of secondary phase with composition Ce9Pd22Al69 that likely was the compound CePd3Al9 [15]. The XRD data were

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analyzed by Rietveld method using the program MRIA [16] (see Fig. 1) down to the residuals: Rp = 0.0327, Rwp = 0.0423, Rexp = 0.0287, χ2 = 2.038. The refined lattice parameters were a = 11.4889(17) Å, b = 4.4277(8) Å, c = 9.1465(9) Å, β = 123.16(1)˚. Magnetic measurements were performed in the temperature range 1.71 – 400 K and in external fields up to 5 T using a Quantum Design SQUID magnetometer. The electrical

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resistivity was measured over the temperature interval 2 – 300 K and in magnetic fields up to 9 T employing a Quantum Design PPMS platform and standard ac four-probe technique. Specific heat measurements were carried out in the temperature range 2 – 300 K by relaxation

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method using the same Quantum Design PPMS platform.

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3. Crystal structure

The crystal structure determined for CePd2Al8 is of a new type. In the unit cell, all the

crystallographic sites are fully occupied by atoms of the same type. The Ce atom in located at the 2a site, and coordinated by 14 Al atoms forming a polyhedron derived from a cuboctahedron (Fig. 2). Interatomic Ce-Al distances of 3.164-3.480 Å are comparable with the sum of the Ce and Al atomic radii (3.26 Å [17]). Next-nearest neighbors of the Ce atom are six Pd atoms with Ce-Pd separation of 3.684-3.806 Å, which is much longer than the sum of the atomic radii of Ce and Pd (3.20 Å [17]). The Pd atoms are arranged around the Ce central atom into a distorted octahedron with Pd-Pd distances ranging from 4.289 to 6.142 Å. In the crystal structure of CePd2Al8, the Ce atoms lie in the ab-plane so that the shortest Ce-Ce contacts within the plane are 2×4.415 Å and 4×6.142 Å, whereas those 3

ACCEPTED MANUSCRIPT between the planes are essentially longer being 7.99 and 9.126 Å. Along the b-direction, the Ce-centered Al polyhedra are packed with sharing their faces, while along the a-direction they are edge-sharing. In such a way, slabs of the Ce polyhedra are arranged parallel to the (ab) plane (see Fig. 3a). Coordination polyhedron of the Pd atom located at the 4i site can be described as a

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severely distorted cube of eight Al atoms with interatomic Pd-Al contacts of 2.488-2.727 Å. Each Pd-centered polyhedron is edge sharing with five other Pd polyhedra forming a corrugated slab parallel to the (201) plane (see Fig. 3b). Within the slab Pd-Pd interatomic distances range from 4.415 Å to 4.466 Å. In turn, fourteen Pd-Pd contacts between the slabs

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range from 5.899 Å to 6.280 Å.

Four independent crystallographic Al sites possess irregular environments with coordination numbers from 7 to 9, and Al-Al contacts from 2.488 to 2.900 Å, i.e. close or

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shorter than the sum of the metallic radii of Al atom (2.86 Å [10]).

The slabs of the Ce-centered polyhedra and the Pd-centered polyhedra mutually interpenetrate to form a three-dimensional network by sharing quadrilaterals composed of four Al atoms (see Fig. 3c). The layered arrangement of the crystal structure of CePd2Al8 is highly unusual for ternary aluminides of rare-earth metals and group VIII d-elements with Al

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content ≥70 at.%. This is because all the hitherto known structures can be divided into two main groups [18]. In the first group, the structures of YbFe2Al10 [19], NdRh4Al15.37 [20], Ce2Ru3Al15 [21], and La2NiAl7 [22] can be described as packing RE-centered polyhedra of T and Al atoms, sharing their corners, edges, or/and faces. It is worth emphasizing that RE-Al

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and RE-T distances are of similar magnitude, approximately equal or longer by less than 10% compared to the sum of the respective atomic radii. These structures exhibit relatively strong RE-Al, RE-T, T-Al, and Al-Al interactions. In the second group of structures, represented by

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EuCo2Al9 [23], PrCo2Al8 [24] and other RET2R8 phases (RE = rare earth, T = Co, Fe, Ru; R = Al, Ga) with the CeFe2Al8-type structure [2-4], CeRu3−xAl10+x (x = 0.17) [25], Gd3Ni5Al19 [26], and Pr2Co6Al19 [24], interatomic distances RE-T are appreciably longer than those of RE-Al distances, which implies that the RE-T contacts are non-bonding. These structures are built of two types of Al polyhedra: RE- and T-centered ones. Interestingly, in the structures of CeRu3Al10, Gd3Ni5Al19, and Pr2Co6Al19, the RE-centered polyhedra form layers parallel to (ab), (ab), and (bc) plane, respectively, whereas the T-centered polyhedra form threedimensional networks. In the unit cells of PrCo2Al8, CeRu3Al10, and Pr2Co6Al19, the T-T distances are close to the sums of the respective transition metal metallic radii (rCo = 1.253 Å, rRu = 1.34 Å [17]), being 2.843 Å, 3.040 Å, and 2.939 Å, respectively. Remarkably, also RE4

ACCEPTED MANUSCRIPT RE bonding is fairly weak in these structures – the RE-RE distances are equal (just in the case of EuCo2Al9 [23]) or 10-16% longer than the sums of the respective metallic radii of the RE elements [2-4, 24-26]. Most recently, the formation of a new platinum cerium aluminide Ce1-xPt6Al16+2x (x = 0.207) was reported [27], with a crystal structure remarkably different from those found for

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other aluminides with high Al content. The unit cell of Ce1-xPt6Al16+2x is composed of three types of polyhedra: Ce-centered polyhedra made of Pt and Al atoms, Pt-centered polyhedra of Al atoms, and Al-centered polyhedra build of Pt and Al atoms. In spite of the low Ce content (3.5 at.%), comparable to that of Nd (4.9 at.%) in NdRh4Al15.37 [20], the shortest Ce-Ce

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contact is there equal to 4.339 Å, whereas in NdRh4Al15.37 the Nd-Nd separation is much longer, namely 6.8799 Å.

To conclude, the new compound CePd2Al8 is characterized by the presence of strong

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Ce-Al, Pd-Al, and Al-Al bonding and the absence of Ce-Pd and Pd-Pd bonding. The Ce-Ce contact of 4.415 Å is 21% longer than twice the Ce atomic radius (rCe = 1.825 Å), and therefore must be regarded as non-bonding.

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4. Physical properties

As shown in the Fig. 4, over an extended temperature range, CePd2Al8 exhibits a strongly temperature-dependent paramagnetism that can be described above 50 K by the Curie-Weiss (CW) formula with the effective magnetic moment µeff = 2.29 µB and the

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paramagnetic Curie temperature θp = −5.3 K. At lower temperatures, χ(T) deviates from the CW law, likely due to gradual depopulation of crystalline electric field (CEF) energy levels.

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The experimental value of µeff is smaller than that calculated within the Russell-Saunders coupling scenario for trivalent Ce ions (g[J(J+1)]1/2 = 2.54), thus hinting at somewhat unstable character of the Ce-4f shell. The obtained θp value is not compatible with ferromagnetic ordering in CePd2Al8 (see below) being negative and about twice smaller than TC. This finding might indicate that electronic correlations in the studied compound are strongly influenced by antiferromagnetic Kondo interactions. A clear evidence for the long-range magnetic ordering in CePd2Al8 comes from the low-temperature magnetic data. The characteristic variations of the magnetization as functions of temperature and magnetic field (see the insets to Fig. 4) reflect a ferromagnetic nature of the electronic ground state. The Curie temperature, defined as an inflection point on the σ(T) 5

ACCEPTED MANUSCRIPT curve, amounts to TC = 9.5 K. The magnetization isotherm taken at 1.71 K saturates in strong magnetic fields, reaching in 5 T a value of 8.8 emu/g that corresponds to the ordered magnetic moment of 0.89 µB. The latter value is only a fraction of the magnetic moment calculated for a free Ce3+ ion (gJ = 2.15), and it should be associated with a Kramers doublet being the CEF ground state upon lifting the degeneracy of the cerium 2F5/2 multiplet in the CEF potential.

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Moreover, in view of the likely Kondo character of the compound one can expect that the low-temperature magnetic moment is somewhat reduced due to Kondo screening effect. A characteristic feature of the ferromagnetic state in CePd2Al8 is a rapid rise of the magnetization in weak magnetic fields and very large remanence of about 93% of the

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saturation value.

Further indication of the ferromagnetic ordering in CePd2Al8 comes from the heat capacity data. As visualized in the inset to Fig. 5, the temperature dependence of the specific

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heat shows a mean-field type anomaly at the Curie temperature TC = 9.5 K. The jump in C(T) amounts to about 12 J/(mol K), that is close to the value predicted within the molecular field approach for systems with the effective spin J = ½ (appropriate for Ce-based compounds with doublet CEF ground state). The entropy released by TC, estimated by integrating the C/T versus T data (see the inset to Fig. 5), equals to about 4.4 J/(mol K) = 0.76Rln2 (R is the gas

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constant). The substantial reduction of the entropy S with respect to the value expected for a doublet ground state [because of nonzero phonon contribution to C(T) in the considered temperature region, the calculated value overestimates the actual magnitude of the magnetic entropy] presumably arises from the Kondo interactions. Applying the Bethe Ansatz solution

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(J = ½) of S = 0.65Rln2 released at the Kondo temperature, one finds from the data shown in the inset to Fig. 5 the estimate for TK being only slightly smaller than TC. At 2 K, the lowest temperature in the measurement performed for CePd2Al8, the C/T

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ratio attains a value of about 60 mJ/(mol K2), which signals a moderate enhancement of the electronic specific heat. In the paramagnetic state, the C(T) variation shows a regular sigmoidlike shape with a tendency towards saturation on approaching the room temperature (see Fig. 5). The specific heat value measured at 300 K is about 266 J/(mol K) that is still somewhat smaller that the Dulong-Petit limit 3nR = 274.4 J/(mol K) for this compound (n stands for the number of atoms in the formula unit). As displayed in Fig. 6a, the electrical resistivity of CePd2Al8 varies with temperature in a manner characteristic of Ce-based Kondo lattices. Distinct bending in ρ(T) near 100 K can be attributed to an interplay of Kondo and CEF interactions, while a faint maximum near 15 K probably manifests a crossover from incoherent to coherent Kondo regime. At the Curie 6

ACCEPTED MANUSCRIPT temperature TC = 9.5 K, one observes a knee in ρ(T) that gives rise to a sharp maximum in the temperature derivative of the resistivity (note the inset to Fig. 6a). The residual resistivity measured at 2 K is only 0.47 µΩcm, which together with large residual resistivity ratio RRR =

ρ(300K)/ρ(2K) ≈ 75 indicates a high quality of the polycrystalline sample measured. In magnetic fields applied perpendicular to the electric current, the onset of the

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ordered state in CePd2Al8 moves to higher temperatures with increasing field, as expected for ferromagnets, and simultaneously it becomes less and less discernible in the ρ(T) data (see Fig. 6b). At the lowest temperatures, the transverse (H ⊥ i) magnetoresistance (MR), defined ∆ρ

ρ

=

ρ (T , H ) − ρ (T , H = 0) , is positive, yet above a certain temperature that increases ρ (T , H = 0)

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as

with increasing µ0H, MR becomes negative. This behavior is characteristic for Kondo lattices,

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where magnetic field influences the crossover from coherent to incoherent Kondo state and then brings about a gradual suppression of the Kondo interactions along with an increase in the field strength. The latter effect is clearly observed in the ρ(T) data of CePd2Al8 taken above TC (see Fig. 6b).

As can be inferred from the upper panel of Fig. 7, the magnitude of MR in the ordered ∆ρ

ρ

is an almost linear function of magnetic field, and in µ0H = 9 T

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state is very high. At 2 K,

the positive MR reaches about 330%. With increasing temperature, MR measured in this field rapidly decreases down to 1.5% at 8 K, and then jumps to a large negative value of −43% at 9 K. In the paramagnetic state, MR observed in 9 T is initially negative, yet its magnitude

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quickly decreases with increasing temperature, and above 20 K, MR attains positive values ∆ρ

ρ

(H) isotherms taken above

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again (see the lower panel of Fig. 7). The overall shape of the

TC is typical for Kondo systems with ferromagnetic correlation and sizeable contribution due to classical Lorentz magnetoresistance effect.

4. Summary The novel cerium palladium aluminide, CePd2Al8, was synthesized by direct reaction of the elements. Its crystal structure was determined from the single crystal X-ray diffraction data to be monoclinic of a new type (space group C2/m). The derived structure can be

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ACCEPTED MANUSCRIPT represented by slabs of Ce-centered polyhedra running parallel to (ab) plane and corrugated slabs of Pd-centered polyhedra propagating parallel to (201) plane. The results of thermodynamic and electrical transport measurements revealed that CePd2Al8 exhibits fairly well localized magnetism due to trivalent Ce ions. At TC = 9.5 K, the compound undergoes a ferromagnetic phase transition, which gives rise to distinct

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singularities in the temperature variations of the magnetic susceptibility, electrical resistivity and specific heat. The observations of reduced effective and saturation magnetic moments, negative paramagnetic Cure temperature, reduced entropy released by TC, and enhanced electronic specific heat altogether point to the prevalence of Kondo screening interactions. In

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addition, the temperature-dependent electrical resistivity of CePd2Al8 as well as the temperature and magnetic field variations of its magnetoresistance are characteristic of Kondo

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lattices with moderately-enhanced heavy fermion ground states.

Acknowledgement

The work was performed under support of RFBR (research Grant No. 15-03-04434). The X-ray part of this research was supported by the Russian Ministry of Science and

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Education, grant No. RFMEFI61616X0069.

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26. R.E. Gladyshevskii, K. Cenzual, and E. Parthé, The crystal structure of orthorhombic Gd3Ni5Al19, a new representative of the structure series R2+mT4+mAl15+4m, J. Solid State Chem. 100 (1992) 9-15.

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48-57], Solid State Sci. 65 (2017) 117-118.

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ACCEPTED MANUSCRIPT Figure captions Figure 1. The experimental XRD pattern of CePd2Al8 (black) and the Rietveld refinement difference curve (red). Vertical bars denote the calculated positions of the diffraction peaks.

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Figure 2. Coordination polyhedra of the atoms in the crystal structure of CePd2Al8. Ce atoms are drawn as big green balls, Pd atoms – as small blue ball, and Al atoms – as middle size pink balls.

Figure 3. Projection of the crystal structure of CePd2Al8 onto ac-plane. (a) Ce polyhedra

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slabs; (b) Pd polyhedra slabs; (c) three dimensional network (half of Pd polyhedra is omitted).

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Figure 4. Temperature dependence of the inverse magnetic susceptibility of CePd2Al8 measured in a magnetic field of 0.1 T. Solid line represents the fit of Curie-Weiss law to the experimental data. Upper inset: low-temperature variation of the magnetization in CePd2Al8 measured in a field of 0.1 T. Lower inset: field variations of the magnetization in CePd2Al8 taken at 1.71 K with increasing (full symbols) and decreasing (open symbols) magnetic field strength.

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Figure 5. Temperature dependence of the specific heat of CePd2Al8. Inset: low-temperature variations of the specific heat over temperature ratio (left-hand side axis) and the entropy (right-hand side axis) of CePd2Al8.

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Figure 6. (a) Temperature dependence of the electrical resistivity of CePd2Al8. Inset: temperature derivative of the electrical resistivity at the lowest temperatures. (b) Low-

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temperature variations of the electrical resistivity of CePd2Al8 measured in applied magnetic field of different strength.

Figure 7. Magnetic field variations of the transverse magnetoresistivity of CePd2Al8 measured at several temperatures in the magnetically ordered (upper panel) and paramagnetic (lower panel) state.

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ACCEPTED MANUSCRIPT Table 1. Crystallographic data of CePd2Al8 Pearson code

mS22

Space group, Z

C 2/m (No 12), 2

Lattice parameters

a = 11.463(12) Å b = 4.4147(4) Å

β = 123.12(7)˚ Cell volume (Å3), Formula weight 386.8(7), 568.76 4.884

Range in h,k,l

0≤h≤20, 0≤k≤7, -16≤l≤13

Range in θ

2.10≤ θ ≤29.97

Reflections collected / unique /Rint 1268 / 1224 / 0.0387 900

Number of parameters

36

Absorption coefficient (mm-1)

5.899

Extinction coefficient

0.0101(16)

R[F2>2σ(F2)]

0.0358

wR(F2)

0.0974

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Reflections with I > 2σ(I)

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Calculated density (g/cm3)

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c = 9.126(11) Å

GooF on F2

0.789

Atom Wyckoff

Ce

x/a

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site

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Table 2. Atomic positions and displacement parameters in the crystal structure of CePd2Al8 y/b

z/c

Ueq, Å2

2a

0

0

0

0.00642(14)

4i

0.19342(6)

0

0.76869(7)

0.00717(14)

4i

0.0675(3)

0

0.4144(3)

0.0095(4)

4i

0.2977(3)

0

0.3692(3)

0.0085(4)

Al3

4i

0.3402(3)

0

0.1021(3)

0.0082(4)

Al4

4i

0.6223(3)

0

0.2964(3)

0.0080(4)

Pd Al1 Al2

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Table 3. Selected interatomic distances in the crystal structure of CePd2Al8

2 Al2

3.230(5)

Al4

2.664(5)

4 Al3

3.311(5)

Al3

2.735(5)

2 Al1

3.420(5)

2 Al1

2.780(3)

2 Al3

3.480(5)

2 Al4

2.810(3)

4 Pd

3.684(3)

Ce

3.230(5)

2 Pd

3.806(3) Al3

Pd

2.548(4)

Al4

2.488(3)

2 Pd

2.628(2)

Al1

2.505(4)

Al4

2.708(5)

Al3

2.548(4)

Al2

2.735(5)

2 Al2

2.570(2)

2 Al3

2.900(4)

2 Al3

2.628(2)

2 Ce

3.311(5)

Al1

2.727(5)

Ce

3.480(5)

Pd

2.505(4) Al4

Pd

2 Al4

2.677(3)

Pd

2.727(5)

Al1

2.735(5)

2 Al2

2.780(3)

Al2

2.884(5)

Ce

3.420(5)

RI PT

2.570(2)

M AN U

Pd

2.488(3)

TE D

Al1

3.164(3) Al2

EP

Pd

4 Al4

Al2

2.664(5)

2 Al1

2.677(3)

Al3

2.708(5)

2 Al2

2.810(3)

2 Ce

3.164(3)

AC C

Ce

Atom to atom d, Å

SC

Atom to atom d, Å

13

AC C EP TE D

M AN US

CR

IP T

AC C EP TE D

M AN US

CR

IP T

AC C EP TE D

M AN US

CR

IP T

AC C EP TE D

M AN US

CR

IP T

AC C EP TE D

M AN US

CR

IP T

AC C EP TE D

M AN US

CR

IP T

AC C EP TE

D

M AN US

CR

IP T

AC C

EP

TE

D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

The formation of a novel compound CePd 2Al8 was established. ACCEPTED MANUSCRIPT

•

The crystal structure of CePd2Al8 was refined from the single-crystal X-ray diffraction data.

•

The low-temperature thermodynamic and electrical behaviour in CePd2Al8 was determined.

•

The compound was found to order ferromagnetically and exhibit Kondo lattice behaviour.

AC C

EP

TE D

M AN U

SC

RI PT

•