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Above Curie temperature, MnBi crystals are aligned in situ along the c-axis in a Bi matrix by a high fabrication magnetic field H f of 10 T. Magnetic testing shows a pronounced anisotropy in magnetization in directions normal and parallel to the fabrication field, resulting from the alignment. The successful alignment m v result from the fact that the easy magnetization direction is along the c-axis of MnBi and the high fabrication field of 10 T is large enough to rotate the )MnBi crystal to this direction even though the temperature is above the Curie temperature. 相似文献
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Determination of the magnetocaloric effect associated with martensitic transition in Ni46Cu4Mn38Sn12 and Ni50CoMn34In15 Heusler alloys
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This paper presents a study of the inverse magnetocaloric effect (MCE) corresponding to martensitic transition using various experimental approaches for Ni46Cu4Mn38Sn12 and Ni50CoMn34In15 Heusler alloy. Through heat capacity measurements,it is found that the "giant inverse MCE" upon martensitic transition evaluated by the Maxwell relation in these alloys are unphysical results. This is due to the coexistence of both martensitic and austenitic phases,as well as thermal hysteresis during martensitic transition. However,careful study indicates that the spurious results during martensitic transition can be removed using a Clausius-Clapeyron equation based on magnetization measurements. 相似文献
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对La2-xSrxCuO4系列(x=0.06~0.20)样品的电阻率和霍尔系数等输运特性进行了系统研究.电阻率随温度变化的实验结果表明,对低掺杂样品,在正常态区域(T>Tc),随Sr掺杂量的增加,各样品在低温区超导转变温度附近均发生了金属-绝缘体转变,且转变温度TMl随掺杂量的增加逐渐降低;对于最佳掺杂样品,其金属-绝缘体转变行为变得非常不明显,到x=0.18时完全消失.对正常态样品的霍尔系数而言,随温度的降低逐渐增大,且随Sr掺杂量的增加显示减小.表明载流子浓度随掺杂量的增加而增加.在低掺杂时,接近Tc的温区内霍尔系数RH迅速增大,随着掺杂量的增加Tc附近霍尔系数的增大变缓.霍尔系数在Tc附近的增大,表明低温区载流子浓度减少.电阻率和霍尔系数在低温区电输运的这种反常行为可从载流子的局域化角度给予初步解释. 相似文献
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