THERMAL, MAGNETIC AND STRUCTURAL ASPECTS OF TRANSITIONS IN Mno.63Cro~7As. THERMODYNAMIC PROPERTIES FROM 10 TO 350 K
نویسندگان
چکیده
Subambient crystallographic and magnetic structures and heat capacity on Mn0.63Cro.37As are measured below 350 K. A complex first order magnetic (helimagnetic H : to H:type) and structural (MnPto MnP-type) transition, accompanied by a discontinuous unit cell volume change, and a second order magnetic [heli-(H,.) to paramagnetic] transition are observed at 165 and 219 K, respectively. The thermodynamic functions are derived and the thermodynamic characteristics of the transitions are discussed. The enthalpy and entropy of the combined MnP,H,: to MnP,H: and MnP,H,. ~ MnP,P-type transitions are assessed to be 124.8R K and 0.749R, respectively. Two different models for the deconvohition of the magnetic heat-capacity envelope into contributions from the MnP ,H: to MnP,H: and the MnP,H C # MnP,P-type transitions are considered.
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