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Proton spin-lattice relaxation time of triglycine sulfate (NH2CH2COOH)3 · H2SO4 near the transition point
Volume 65A, number 4
PHYSICS LETTERS
20 March 1978
PROTON SPIN-~-LATTICERELAXATION TIME OF TRIGLYCINE SULFATE (NH2CH2COOH)3 H2SO~NEAR THE TRANSITION POINT Y. TSUJIMI, M. KASAHARA and I. TATSUZAKI Research Institute ofApplied Electricity, Hokkaido University, Sapporo, Japan Received 2 November 1977
The temperature dependence of the proton spin-lattice relaxation time T1 of triglycine sulfate (NH2CI-12C001-1)3 1-12 SO4 is investigated near the transition point under several conditions. Any anomalous behavior ofT1 cannot be ob-
served in contrast with an earlier report by Brosowski et a!.
Brosowski eta!. [1] have1reported near T~ainnon-monotriglycine tonic anomaly of proton Tj sulfate (TGS). The temperature dependence of this anomaly is very similar to that of the dielectric anomaly at high frequency [2] which has double peaks with a minimum at T~.But a monodispersive Debye type model which describes the dielectric anomaly cannot explain this NMR result. If one estimates the relaxation time of polarization from this T1 anomaly by using the Debye model, an unreasonable order of relaxation time is obtained [1]. Recently, MUller and Petersson [3] proposed that some resonance type motion having a frequency of about 200 MHz causes this T1 anomaly as a result of the coupling with relaxation motion which is responsible for the dielectric anomaly. We are interested in these studies and report in this letter the dependence ofT1 on temperature, direction of static mafnetic field H0, sample preparation and Larmor frequency. Three single crystals of TGS were grown by slow cooling from aqueous solutions. Two of them were grown in the ferroelectric phase (sample I and 2) and the other in the paraelectric phase (sample 3) in order to study the sample dependence of T1. For TGS solution, we used deionized water, the electric conductivity of which is 0.2—0.3 p~2~/cm in order to remove paramagnetic We cut single crystals to cylindrical ions formas10possible. mm in diameter and about 15 mm long. In order to deterniine T~of each 366
sample, plate of about 3 X used 3 X for 1 mm wasmeasurecut from thethe same mother crystal NMR ments and the dielectric constant Eb along the ferroelectric b axis was measured. (We refer to Hoshino’s axial system [4] .) Three samples showed a peak of at the same temperature 49.25°C(fig. 2). A homemade pulse spectrometer was operated at ~L = 25.85 MHz to observe the dependence of T 1 on the direction of H0 and sample preparation. Temperature between 40 and 60°Cwas regulated by the same method as reported by Hikita et a!. [5]. In order to reduce experimental error, we improved the signal-to-noise ratio by 40 times accumulation of the free induction decay signals. The experimental error in T1 was less than about 2% in the paraelectric phase. Though the configuration that H1 is applied parallel to the b axis was tried following ref. [1] piezoelectric lines were present in a free induction decay signal and reliable results could not be obtained, It was found, however, that no piezoelectric lines were observed if the direction of H1 was chosen to be parallel to the c axis of the sample 1. Thus our all measurements were made with this direction of H1, though unfavorable piezoelectric lines appear for the samples 2 and 3 as mentioned later. Fig. 1 shows the results obtained at 25.85 MHz in sample 1. When the direction ofH0temperature is perpendicular 1 behaves against almost to the b axis, T1behavior in fig. la. It is seen that the the same as the temperature dependence of T 1does not depend on 1~ ,
Volume 65A, number 4 28
PHYSICS I
-—---
9
—-~-~----~---—~-
LETTERS
20 March 1978
Table I Activation energy in eV. Blincet al.
25
-
Brosowski et al.
8
0
20
work
T> Tc
0.23
0.22
0.18
T
0.23
0.25
0.21
with Bruker B-KR 322s operating at 60 MHz. The result obtained the not sample 1 is shown fig. 2 and the anomaly wasinalso observed in thisincase.
8 0
Present
near Tc becomes larger at higher frequency. In order to check this frequency dependence, we observed T1
•
8
[1]
5
0
(b)
We studied the temperature dependence ofT1 near
5 40
45
~0
55
•
1on the direction of H Fig. 1. The dependence of T~ sample 1 at 25.85 MHz. (a)H0 lb. (b) L(H0, b)
=
0 in 41°,
1change. 0 direction though the absolute values of T~ Thus, in the following observation, T 1 was measured with H0 making an angle of 41°with the b axis, because a good signal-to-noise ratio was obtained at this angle. In order to study the sample dependence of T1, we performed T1 measurements using samples 2 and 3, which were annealed for 48 hour at 120°C.In these samples the experimental error was slightly larger owing to the appearance of piezoelectric lines with small intensity. And the anomalous behavior in T1 was not observed. According to the experimental results of Brosowski et al. [I], the anomaly ofT1 H
0
12
0
0
0
0
0
-
0
0
(Ti~ (T~’)exp= (T~’)nor+ (T~)ano+ (T~’)~~,
where the suffix “nor” means relaxation owing to the hindered rotation of NH3 groups, “ano” owing to the polarization fluctuation and “ion” owing to the paramagnetic ions. Since (TjA)e~pin the present study is of the same order as the values of Brosowski et al. [11 and Blinc et al. [6] in spite of paying attention to removing paramagnetic ions, (Tf~)~~ seems not to make serious a contribution to (Tj~’)exp.Consequently it follows that the three-fold hindered rotation of NH3 groups essentially contributes to (Tf~)exp.The activation energy of this hindered rotation was calculated by using the well-known BPP theory [7] from the data shown in fig. I a and is shown in table 1. The calculated activation energy may contain a relatively large error,because T1 was observed in the narrow
Osaka University permitting us to use the B-KR 322s and forforreading and criticizing the Bruker manuscript. We are also grateful to Dr. T. Asai and Dr.
0 0
I
43
anomaly 1)exp of may T1 be cannot givenbe byobserved. a sum of three An experimental parts as
by Blinc et al. [6]. We would like to thank Professor H. Kiriyama of
.~:0:
I 40
T~of TGS single crystal under several conditions. In contrast to the report of Brosowski et al. [1], any
temperature region. However, the temperature dependence of T1 is essentially in accord with that reported
1
-
0C) T(
•
I ~5
I
60
Fig. 2. The temperature dependence of T 5 in sample 1 at 60.00 MHz and of the reciprocal dielectric constant. The direction of H0 is the same as in fig. lb. =
[61
0
Y. Furukawa University for their help in collecting dataofatOsaka 60 MHz. This work was supported in part by a Grant-in-Aid for Scientific Research from .
the Ministry of Education. 367
Volume 65A, number 4
PHYSICS LETTERS
20 March 1978
References
[4] S. Hoshino, Y. Okaya and R. I’epinsky, Phys. Rev. 115 (1959) 323.
[1] G. Brosowski, W. Buchheit, D. MOller and J. Petersson, Phys. Stat. Sol. (b) 62 (1974) 93. [2] G. Luther and n.E. Müser, Z. Naturforsch. 24a (1969) 389. [3] D. MUller and J. Petersson, Phys. Stat. Sol. (b) 78 (1976) 191.
[SI T. Hikita, K. Sakata and I. Tatsuzaki, J. Phys. Soc. Japan 34 (1973) 1248. [6] R. Blinc, C. Lahajnar, M. Pinter and I. Zupancic, i. Chem. Phys. 44 (1966) 1784. [71N. Bloensbergen, E.M. Purcell and R.V. Pound, Phys. Rev. 73(1948)679.
368
PHYSICS LETTERS
20 March 1978
PROTON SPIN-~-LATTICERELAXATION TIME OF TRIGLYCINE SULFATE (NH2CH2COOH)3 H2SO~NEAR THE TRANSITION POINT Y. TSUJIMI, M. KASAHARA and I. TATSUZAKI Research Institute ofApplied Electricity, Hokkaido University, Sapporo, Japan Received 2 November 1977
The temperature dependence of the proton spin-lattice relaxation time T1 of triglycine sulfate (NH2CI-12C001-1)3 1-12 SO4 is investigated near the transition point under several conditions. Any anomalous behavior ofT1 cannot be ob-
served in contrast with an earlier report by Brosowski et a!.
Brosowski eta!. [1] have1reported near T~ainnon-monotriglycine tonic anomaly of proton Tj sulfate (TGS). The temperature dependence of this anomaly is very similar to that of the dielectric anomaly at high frequency [2] which has double peaks with a minimum at T~.But a monodispersive Debye type model which describes the dielectric anomaly cannot explain this NMR result. If one estimates the relaxation time of polarization from this T1 anomaly by using the Debye model, an unreasonable order of relaxation time is obtained [1]. Recently, MUller and Petersson [3] proposed that some resonance type motion having a frequency of about 200 MHz causes this T1 anomaly as a result of the coupling with relaxation motion which is responsible for the dielectric anomaly. We are interested in these studies and report in this letter the dependence ofT1 on temperature, direction of static mafnetic field H0, sample preparation and Larmor frequency. Three single crystals of TGS were grown by slow cooling from aqueous solutions. Two of them were grown in the ferroelectric phase (sample I and 2) and the other in the paraelectric phase (sample 3) in order to study the sample dependence of T1. For TGS solution, we used deionized water, the electric conductivity of which is 0.2—0.3 p~2~/cm in order to remove paramagnetic We cut single crystals to cylindrical ions formas10possible. mm in diameter and about 15 mm long. In order to deterniine T~of each 366
sample, plate of about 3 X used 3 X for 1 mm wasmeasurecut from thethe same mother crystal NMR ments and the dielectric constant Eb along the ferroelectric b axis was measured. (We refer to Hoshino’s axial system [4] .) Three samples showed a peak of at the same temperature 49.25°C(fig. 2). A homemade pulse spectrometer was operated at ~L = 25.85 MHz to observe the dependence of T 1 on the direction of H0 and sample preparation. Temperature between 40 and 60°Cwas regulated by the same method as reported by Hikita et a!. [5]. In order to reduce experimental error, we improved the signal-to-noise ratio by 40 times accumulation of the free induction decay signals. The experimental error in T1 was less than about 2% in the paraelectric phase. Though the configuration that H1 is applied parallel to the b axis was tried following ref. [1] piezoelectric lines were present in a free induction decay signal and reliable results could not be obtained, It was found, however, that no piezoelectric lines were observed if the direction of H1 was chosen to be parallel to the c axis of the sample 1. Thus our all measurements were made with this direction of H1, though unfavorable piezoelectric lines appear for the samples 2 and 3 as mentioned later. Fig. 1 shows the results obtained at 25.85 MHz in sample 1. When the direction ofH0temperature is perpendicular 1 behaves against almost to the b axis, T1behavior in fig. la. It is seen that the the same as the temperature dependence of T 1does not depend on 1~ ,
Volume 65A, number 4 28
PHYSICS I
-—---
9
—-~-~----~---—~-
LETTERS
20 March 1978
Table I Activation energy in eV. Blincet al.
25
-
Brosowski et al.
8
0
20
work
T> Tc
0.23
0.22
0.18
T
0.23
0.25
0.21
with Bruker B-KR 322s operating at 60 MHz. The result obtained the not sample 1 is shown fig. 2 and the anomaly wasinalso observed in thisincase.
8 0
Present
near Tc becomes larger at higher frequency. In order to check this frequency dependence, we observed T1
•
8
[1]
5
0
(b)
We studied the temperature dependence ofT1 near
5 40
45
~0
55
•
1on the direction of H Fig. 1. The dependence of T~ sample 1 at 25.85 MHz. (a)H0 lb. (b) L(H0, b)
=
0 in 41°,
1change. 0 direction though the absolute values of T~ Thus, in the following observation, T 1 was measured with H0 making an angle of 41°with the b axis, because a good signal-to-noise ratio was obtained at this angle. In order to study the sample dependence of T1, we performed T1 measurements using samples 2 and 3, which were annealed for 48 hour at 120°C.In these samples the experimental error was slightly larger owing to the appearance of piezoelectric lines with small intensity. And the anomalous behavior in T1 was not observed. According to the experimental results of Brosowski et al. [I], the anomaly ofT1 H
0
12
0
0
0
0
0
-
0
0
(Ti~ (T~’)exp= (T~’)nor+ (T~)ano+ (T~’)~~,
where the suffix “nor” means relaxation owing to the hindered rotation of NH3 groups, “ano” owing to the polarization fluctuation and “ion” owing to the paramagnetic ions. Since (TjA)e~pin the present study is of the same order as the values of Brosowski et al. [11 and Blinc et al. [6] in spite of paying attention to removing paramagnetic ions, (Tf~)~~ seems not to make serious a contribution to (Tj~’)exp.Consequently it follows that the three-fold hindered rotation of NH3 groups essentially contributes to (Tf~)exp.The activation energy of this hindered rotation was calculated by using the well-known BPP theory [7] from the data shown in fig. I a and is shown in table 1. The calculated activation energy may contain a relatively large error,because T1 was observed in the narrow
Osaka University permitting us to use the B-KR 322s and forforreading and criticizing the Bruker manuscript. We are also grateful to Dr. T. Asai and Dr.
0 0
I
43
anomaly 1)exp of may T1 be cannot givenbe byobserved. a sum of three An experimental parts as
by Blinc et al. [6]. We would like to thank Professor H. Kiriyama of
.~:0:
I 40
T~of TGS single crystal under several conditions. In contrast to the report of Brosowski et al. [1], any
temperature region. However, the temperature dependence of T1 is essentially in accord with that reported
1
-
0C) T(
•
I ~5
I
60
Fig. 2. The temperature dependence of T 5 in sample 1 at 60.00 MHz and of the reciprocal dielectric constant. The direction of H0 is the same as in fig. lb. =
[61
0
Y. Furukawa University for their help in collecting dataofatOsaka 60 MHz. This work was supported in part by a Grant-in-Aid for Scientific Research from .
the Ministry of Education. 367
Volume 65A, number 4
PHYSICS LETTERS
20 March 1978
References
[4] S. Hoshino, Y. Okaya and R. I’epinsky, Phys. Rev. 115 (1959) 323.
[1] G. Brosowski, W. Buchheit, D. MOller and J. Petersson, Phys. Stat. Sol. (b) 62 (1974) 93. [2] G. Luther and n.E. Müser, Z. Naturforsch. 24a (1969) 389. [3] D. MUller and J. Petersson, Phys. Stat. Sol. (b) 78 (1976) 191.
[SI T. Hikita, K. Sakata and I. Tatsuzaki, J. Phys. Soc. Japan 34 (1973) 1248. [6] R. Blinc, C. Lahajnar, M. Pinter and I. Zupancic, i. Chem. Phys. 44 (1966) 1784. [71N. Bloensbergen, E.M. Purcell and R.V. Pound, Phys. Rev. 73(1948)679.
368