Physical Properties Of Spin Glass Alloy Pr₂CuSi₃

Spin glasses are magnetic systems in which long-range orders are destroyed into short-range orders. Materials presenting spin glass behavior are competitive candidates for new generation storage materials due to their unique magnetic properties which is referred as "spin frozen". Spin glass materials with high concentration of magnetic atoms have not been thoroughly explored currently, although the spin frozen phenomenon was observed in many materials, its mechanism is still not clear. Thus, Pr2CuSi3which shows spin glass behavior and has high concentration of magnetic atom Pr, was chose and mainly studied on the influence of annealing time and compression on its transport properties in this paper.Si based ternary alloy Pr2CuSi3samples were prepared by arc melting, and then annealed in a vacuum sintering furnace for different periods. The structure studies were performed by X-Ray diffraction; the physical properties were characterized by Van der Pauw method and standard Four-probe method. It was found that the content of impurity phase decreased as annealing time increased. In low temperature region, as annealing time increases, the Hall coefficient increased while the resistivity decreases after a short increasing. Through analyzing the experiment result before, it shows that the grain size of Pr2CuSi3also extended during annealing procedure. The increasing behavior of Hall coefficient could be attributed to the enhancement of magnetization in the sample which was caused by the growth of the Pr2CuSi3grains. And the main phase was gradually surrounded by the impurity phase as annealing time accumulated, resulting in the impurity scattering level raising, which was account for resistivity increasing; when the gain size of main phase reached a certain point, the resistivity decreased as impurity phase was continually being absorbed. In addition, the inflection point around T=50K was investigated in this paper, it was assumed to be affected by both main phase and impurity phase.The transport properties of Pr2CuSi3samples compressed at optimal pressure (0.72kN) was explored in this paper. The results indicated that Hall coefficient of Pr2CuSi3samples compressed at0.72kN gradually decreased with increasing annealing time in low temperature region, which was caused by the extending of grain size in the condition of sufficiently massive grain. Besides, more detailed investigation has been applied on Pr2CuSi3sample annealing for240H after compressed at0.72kN."Hall Hysteresis" was measured around frozen temperature, the results implied that "Hall Hysteresis" could be used to determine the spin glass behavior and to observe some features of spin glass system; the resistivity measurement of Pr2CuSi3sample annealing for240H after compressed at0.72kN was taken out several times, the results showed a Kondo-like behavior around T=13K, it was considered to derive from the interaction between ferromagnetic cluster and conduction electron; however, the possibility that the impurity could make contribution to this effect can not be rule out in this case.