Open AccessNew material exploration and magnetism researchon Heusler alloys Cr-Co-Ga
Author(s) -
Qian Jin-Feng,
Feng Lin,
Zhu Wei,
Enke Liu,
Tang Xiao-Dan,
Wenhong Wang,
Guangheng Wu,
Fanbin Meng,
Heyan Liu,
Luo Hong-Zhi
Publication year - 2011
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.60.056402
Subject(s) - magnetism , magnetic moment , ferromagnetism , condensed matter physics , curie temperature , materials science , atom (system on chip) , crystal structure , ab initio quantum chemistry methods , ab initio , lattice constant , physics , crystallography , chemistry , molecule , quantum mechanics , computer science , diffraction , optics , embedded system
The crystal structure, magnetism and transport properties of a series alloys from Co2CrGa to Cr2CoGa (Co50-xCrx+25Ga25, x=0—25) have been investigated by the experimental and KKR-CPA-LDA calculation methods. Substituting Cr for Co atoms, the crystal structure changes from L21 type to Hg2CuTi structure, which make, the lattice parameters increase about 0.69% linearly. Also, the ferromagnetic coupling turns to anti-ferromagnetic coupling, that makes the magnetic moment linearly decrease from 3.06μB to nearly zero. Through ab initio study of CPA, it has been found that the extraneous Cr atom at the A site couples anti-ferromagnetically with the Cr atom originally situated at B site with a nearly equal magnitude of magnetic moment, and the magnetic moment of Co atoms occupying the C site decreases from 0.60μB to 0.21μB through the whole substituting process. Based on the results of magnetic measurement and calculation, about 20% atomic disorder in the alloy Cr2CoGa has been confirmed, which is consistent with the observation of the X-ray examination. It is interesting that a non-linear "middle component phenomenon" has been observed in the composition dependence of both Curie temperature and the electrical resistivity. The related discussions is based on the magnetic environment change surrounding the magnetic atoms.