Probing the phase transition of methane with Mössbauer effect in 57Fe impurities

M. Pasternak; P. H. Barrett

doi:10.1016/0038-1098(78)90694-4

Probing the phase transition of methane with Mössbauer effect in ⁵⁷Fe impurities

M. Pasternak^*, P. H. Barrett

^*Corresponding author for this work

School of Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

Abstract

Mossbauer studies were performed in ⁵⁷Fe impurities (0.3% at.) in solid methane, in order to investigate the properties of the order-disorder phase transition taking place at T_c=20.4K. From the temperature dependence of the relative values of the recoil-free-fraction - f - it was found that near T_c a change occurs in the slope of f(T²) without discontinuity in the value of f. A consistent model is proposed by which immediately below T_c both phases, I and II coexist with a gradual evolution of the ordered state (II) on the account of the high temperature plastic state (I). The Debye temperature of phase II (θ_II = 101±7K) increases with respect to that of phase I (θ_I = 72±3K), indicating a hardening in the phonon spectrum and precluding the onset of rotational modes of the disordered molecules.

Original language	English
Pages (from-to)	771-774
Number of pages	4
Journal	Solid State Communications
Volume	27
Issue number	8
DOIs	https://doi.org/10.1016/0038-1098(78)90694-4
State	Published - Aug 1978

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title = "Probing the phase transition of methane with M{\"o}ssbauer effect in 57Fe impurities",

abstract = "Mossbauer studies were performed in 57Fe impurities (0.3% at.) in solid methane, in order to investigate the properties of the order-disorder phase transition taking place at Tc=20.4K. From the temperature dependence of the relative values of the recoil-free-fraction - f - it was found that near Tc a change occurs in the slope of f(T2) without discontinuity in the value of f. A consistent model is proposed by which immediately below Tc both phases, I and II coexist with a gradual evolution of the ordered state (II) on the account of the high temperature plastic state (I). The Debye temperature of phase II (θII = 101±7K) increases with respect to that of phase I (θI = 72±3K), indicating a hardening in the phonon spectrum and precluding the onset of rotational modes of the disordered molecules.",

author = "M. Pasternak and Barrett, {P. H.}",

note = "Funding Information: Work supported in part by the National Science Foundation. Work performed at the University of California, Santa Barbara, during leave from Tel Aviv University.",

year = "1978",

month = aug,

doi = "10.1016/0038-1098(78)90694-4",

language = "אנגלית",

volume = "27",

pages = "771--774",

journal = "Solid State Communications",

issn = "0038-1098",

publisher = "Elsevier Ltd.",

number = "8",

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TY - JOUR

T1 - Probing the phase transition of methane with Mössbauer effect in 57Fe impurities

AU - Pasternak, M.

AU - Barrett, P. H.

N1 - Funding Information: Work supported in part by the National Science Foundation. Work performed at the University of California, Santa Barbara, during leave from Tel Aviv University.

PY - 1978/8

Y1 - 1978/8

N2 - Mossbauer studies were performed in 57Fe impurities (0.3% at.) in solid methane, in order to investigate the properties of the order-disorder phase transition taking place at Tc=20.4K. From the temperature dependence of the relative values of the recoil-free-fraction - f - it was found that near Tc a change occurs in the slope of f(T2) without discontinuity in the value of f. A consistent model is proposed by which immediately below Tc both phases, I and II coexist with a gradual evolution of the ordered state (II) on the account of the high temperature plastic state (I). The Debye temperature of phase II (θII = 101±7K) increases with respect to that of phase I (θI = 72±3K), indicating a hardening in the phonon spectrum and precluding the onset of rotational modes of the disordered molecules.

AB - Mossbauer studies were performed in 57Fe impurities (0.3% at.) in solid methane, in order to investigate the properties of the order-disorder phase transition taking place at Tc=20.4K. From the temperature dependence of the relative values of the recoil-free-fraction - f - it was found that near Tc a change occurs in the slope of f(T2) without discontinuity in the value of f. A consistent model is proposed by which immediately below Tc both phases, I and II coexist with a gradual evolution of the ordered state (II) on the account of the high temperature plastic state (I). The Debye temperature of phase II (θII = 101±7K) increases with respect to that of phase I (θI = 72±3K), indicating a hardening in the phonon spectrum and precluding the onset of rotational modes of the disordered molecules.

UR - http://www.scopus.com/inward/record.url?scp=0017997230&partnerID=8YFLogxK

U2 - 10.1016/0038-1098(78)90694-4

DO - 10.1016/0038-1098(78)90694-4

M3 - מאמר

AN - SCOPUS:0017997230

VL - 27

SP - 771

EP - 774

JO - Solid State Communications

JF - Solid State Communications

SN - 0038-1098

IS - 8

ER -

Probing the phase transition of methane with Mössbauer effect in ⁵⁷Fe impurities

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