TY - JOUR
T1 - Spin fluctuation, thermal expansion anomaly, and pressure effects on the Néel temperature of β -MnM ( M=Ru, Os, and Ir) alloys
AU - Miyakawa, M.
AU - Umetsu, R. Y.
AU - Ohta, M.
AU - Fujita, Asaya
AU - Fukamichi, K.
AU - Hori, T.
PY - 2005/12/1
Y1 - 2005/12/1
N2 - The specific heat and the thermal expansion under ambient pressure and the temperature dependence of magnetic susceptibility under applied pressure have been investigated for β- Mn1-xMx(M=Ru, Os, and Ir) alloys by taking spin fluctuations into consideration. From powder neutron diffractions for β- Mn0.75Os0.25alloys, the magnetic Bragg peaks was observed at 10 K, which is the first direct confirmation of a long-range magnetic order in β -Mn alloys. The relationship between the pressure dependence of the Néel temperature d TNdP and T Nis explained by the Ehrenfest equation. A significantly large thermal expansion coefficient in a wide range of temperature above T Nis clearly correlated with spin fluctuations. At low and finite temperatures, the effects of spin fluctuations as a function of the Néel temperature in both the weak itinerant-electron antiferromagnetic state and intermediate antiferromagnetic state are common to β -Mn alloys, regardless of the kinds of additional elements.
AB - The specific heat and the thermal expansion under ambient pressure and the temperature dependence of magnetic susceptibility under applied pressure have been investigated for β- Mn1-xMx(M=Ru, Os, and Ir) alloys by taking spin fluctuations into consideration. From powder neutron diffractions for β- Mn0.75Os0.25alloys, the magnetic Bragg peaks was observed at 10 K, which is the first direct confirmation of a long-range magnetic order in β -Mn alloys. The relationship between the pressure dependence of the Néel temperature d TNdP and T Nis explained by the Ehrenfest equation. A significantly large thermal expansion coefficient in a wide range of temperature above T Nis clearly correlated with spin fluctuations. At low and finite temperatures, the effects of spin fluctuations as a function of the Néel temperature in both the weak itinerant-electron antiferromagnetic state and intermediate antiferromagnetic state are common to β -Mn alloys, regardless of the kinds of additional elements.
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U2 - 10.1103/PhysRevB.72.054420
DO - 10.1103/PhysRevB.72.054420
M3 - Article
AN - SCOPUS:84871398415
VL - 72
JO - Physical Review B - Condensed Matter and Materials Physics
JF - Physical Review B - Condensed Matter and Materials Physics
SN - 0163-1829
IS - 5
M1 - 054420
ER -