Magnetoresistances and magnetic entropy changes associated with negative lattice expansions in NaZn13-type compounds LaFeCoSi
Hu Feng-Xia (胡凤霞)abc, Qian Xiao-Ling (钱小陵)a, Wang Guang-Jun (王光军)b, Sun Ji-Rong (孙继荣)b, Shen Bao-Gen (沈保根)b, Cheng Zhao-Hua (成昭华)b, Gao Ju (高炬)c
a Department of Physics, Capital Normal University, Beijing 100037, China; b State Key Laboratory of Magnetism, Institute of Physics & Center of Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100080, Chinac Department of Physics, The University of Hong Kong, Hong Kong, China
Abstract Magnetoresistances and magnetic entropy changes in NaZn13-type compounds La(Fe1-xCox)11.9Si1.1(x=0.04, 0.06, and 0.08) with Curie temperatures of 243 K, 274 K, and 301 K, respectively, are studied. The ferromagnetic ordering is accompanied by a negative lattice expansion. Large magnetic entropy changes in a wide temperature range from ~230 K to ~320 K are achieved. Raising Co content increases the Curie temperature but weakens the gnetovolume effect, thereby causing a decrease in magnetic entropy change. These materials exhibit a metallic character below TC, whereas the electrical resistance decreases abruptly and then recovers the metal-like behaviour above TC. Application of a magnetic field retains the transitions via increasing the ferromagnetic ordering temperature. An isothermal increase in magnetic field leads to an increase in electrical resistance at temperatures near but above TC, which is a consequence of the field-induced metamagnetic transition from a paramagnetic state to a ferromagnetic state.
Received: 12 January 2005
Revised: 03 July 2005
Accepted manuscript online:
Fund: Project supported by the State Key Development Program for Basic Research of China (Grant No 1998061303),the National Natural Science Foundation of China (Grant Nos 10474066 and
10174094), and the Beijing Natural Science Foundation of China (Grant No 101
Cite this article:
Hu Feng-Xia (胡凤霞), Qian Xiao-Ling (钱小陵), Wang Guang-Jun (王光军), Sun Ji-Rong (孙继荣), Shen Bao-Gen (沈保根), Cheng Zhao-Hua (成昭华), Gao Ju (高炬) Magnetoresistances and magnetic entropy changes associated with negative lattice expansions in NaZn13-type compounds LaFeCoSi 2005 Chinese Physics 14 2329
Altmetric calculates a score based on the online attention an article receives. Each coloured thread in the circle represents a different type of online attention. The number in the centre is the Altmetric score. Social media and mainstream news media are the main sources that calculate the score. Reference managers such as Mendeley are also tracked but do not contribute to the score. Older articles often score higher because they have had more time to get noticed. To account for this, Altmetric has included the context data for other articles of a similar age.
