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The pressure dependence of the Néel temperature in FeF2
Pergamon Press
Sobd State Commumcations, Vol 17, pp m-vu, 1975
Prmted m Great Bntam
Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids J Phys Chem Sollds (to be publlshed)’ should be cited m references to matenal quoted from this section pnor to the pubkatlon of the relevant article
1
Pulsed field expenments up to 450 kOe have been performed on Fe&F6 sH2 0. We mterpret the data (I) in terms of spm Ham&Oman constants
MC)SSBAUERSPECTRA OF PARAMAGNETIC POWDERS UNDER APPLIED FIELD Fe2+IN FLUOSILICATES
D = 12.3 f 0.2 cm-’ (E = 0.54 cm-’ being known
F Varret, Service de Physique du Sohde et de Resonance Magndtlque, Centre d’Etudes Nucl&ures de Saclay, BP No 2 - 9 1190 Glf-sur-Yvette, France
from EPR data), (n) m terms of axtal-crystal-field parameters S/X = orbital tngonal sphttmg/spm-orbit couphng = 15 f 2, A = - 100 f 7 cm-’ The magnetic axts u found to de-ate from the cnstallographtc c axis by an angle lo < 13< 2’. The a&abatrc coohng obtamed durmg the pulse 1s discussed
We mtroduce magnetization effects mto previous calculations of the Mossbauer hneshape of a paramagnetlc powder under apphed field (which are actually relevant m the case of tiagnetic ions only) In the low-magnemtlon hrmt, hyperfme field effects are accounted for by a tensortal relation between the applied field and the effective field actmg on the Mossbauer nucleus, and for strong fields by a phenomenohIpcal saturation law. We apply this model to the case of Fe- and Zn-fluosticates, at 300,100 and 4 2 K In all cases the magnetization correctlon reveals to be nnportant, and the agreement with preylous single crystal measurements is good. At low temperature we obtam an accurate determination of the prmclpal magnetic hyperfme components m the easy plane, as well as a rough estnnate of the asymmetry parameter 7)
Surular expenments on Fe0 &no&F6 sH20 and Fe,, &no ,&lFb sH20 smgle crystals are reported, m both cases we measure D/g,, = 6.0 f 0 1 cm” Uamg EPR data, we obtam D = 14.3 cm-‘, A - - 75 cm-‘, 6 - 195 cm-’ usmg Mossbauer data, weobtamD= 153cm-1,h--88cm-1, S ‘I 185 cm-’ Recewed 18 November 1974
3
G A Garcta and R. Ingalls, Department of Physics, University of Washmgton, Seattle, WA 98195, U.S A
Recewed 18 November 1974
2
THE PRESSURE DEPENDENCE OF THE Nl?EL TEMPERATURE IN FeFz
A Mossbauer measurement of the pressure dependence of the NCel temperature m FeF2 ISreported Up to the maxm?um pressure of 50 kbar TN increases at the rate of 0 27 f 0 03 ‘K/kbar When ths pressure dependence is converted to volume dependence, the result, d ln TN/d In V = 3.2 + 0 3,ls found to obey the “lo/3 rule” estabhshed by Bloch for a wde variety of antiferromagnetic msulators
PULSED MAGNETIC FIELD STUDY OF Fe2* IN SOME FLUOSILICATES F Varret, Service de Physique du Sohde et de RCsonance MagnCtlque, Centre d’Etudes NuclCalres de Saclay, BP No 2 - 91190 Glf-sur-Yvette, France
Recewed 23 June 1975 111
Sobd State Commumcations, Vol 17, pp m-vu, 1975
Prmted m Great Bntam
Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids J Phys Chem Sollds (to be publlshed)’ should be cited m references to matenal quoted from this section pnor to the pubkatlon of the relevant article
1
Pulsed field expenments up to 450 kOe have been performed on Fe&F6 sH2 0. We mterpret the data (I) in terms of spm Ham&Oman constants
MC)SSBAUERSPECTRA OF PARAMAGNETIC POWDERS UNDER APPLIED FIELD Fe2+IN FLUOSILICATES
D = 12.3 f 0.2 cm-’ (E = 0.54 cm-’ being known
F Varret, Service de Physique du Sohde et de Resonance Magndtlque, Centre d’Etudes Nucl&ures de Saclay, BP No 2 - 9 1190 Glf-sur-Yvette, France
from EPR data), (n) m terms of axtal-crystal-field parameters S/X = orbital tngonal sphttmg/spm-orbit couphng = 15 f 2, A = - 100 f 7 cm-’ The magnetic axts u found to de-ate from the cnstallographtc c axis by an angle lo < 13< 2’. The a&abatrc coohng obtamed durmg the pulse 1s discussed
We mtroduce magnetization effects mto previous calculations of the Mossbauer hneshape of a paramagnetlc powder under apphed field (which are actually relevant m the case of tiagnetic ions only) In the low-magnemtlon hrmt, hyperfme field effects are accounted for by a tensortal relation between the applied field and the effective field actmg on the Mossbauer nucleus, and for strong fields by a phenomenohIpcal saturation law. We apply this model to the case of Fe- and Zn-fluosticates, at 300,100 and 4 2 K In all cases the magnetization correctlon reveals to be nnportant, and the agreement with preylous single crystal measurements is good. At low temperature we obtam an accurate determination of the prmclpal magnetic hyperfme components m the easy plane, as well as a rough estnnate of the asymmetry parameter 7)
Surular expenments on Fe0 &no&F6 sH20 and Fe,, &no ,&lFb sH20 smgle crystals are reported, m both cases we measure D/g,, = 6.0 f 0 1 cm” Uamg EPR data, we obtam D = 14.3 cm-‘, A - - 75 cm-‘, 6 - 195 cm-’ usmg Mossbauer data, weobtamD= 153cm-1,h--88cm-1, S ‘I 185 cm-’ Recewed 18 November 1974
3
G A Garcta and R. Ingalls, Department of Physics, University of Washmgton, Seattle, WA 98195, U.S A
Recewed 18 November 1974
2
THE PRESSURE DEPENDENCE OF THE Nl?EL TEMPERATURE IN FeFz
A Mossbauer measurement of the pressure dependence of the NCel temperature m FeF2 ISreported Up to the maxm?um pressure of 50 kbar TN increases at the rate of 0 27 f 0 03 ‘K/kbar When ths pressure dependence is converted to volume dependence, the result, d ln TN/d In V = 3.2 + 0 3,ls found to obey the “lo/3 rule” estabhshed by Bloch for a wde variety of antiferromagnetic msulators
PULSED MAGNETIC FIELD STUDY OF Fe2* IN SOME FLUOSILICATES F Varret, Service de Physique du Sohde et de RCsonance MagnCtlque, Centre d’Etudes NuclCalres de Saclay, BP No 2 - 91190 Glf-sur-Yvette, France
Recewed 23 June 1975 111