Spin-glass behavior in Mn alloys

Metallic spin-glasses beyond mean-field: an approach to the impurity-concentration dependence of the freezing temperature

“…This proves the correctness of the ansatz (6). The energy per spin is [34], and consequently, (15) reduces to the TAP result…”

“…For this system, one has a 0 = 3.61 Å, n = 8.5 × 10 28 m −3 , T F = 7 eV, k F = 1.36 Å−1 , S = 1.95, and J sd = 0.21 eV [45]. As reported elsewhere [6,22], the resistivity in these alloys can be roughly represented by the linear dependence ρ = 400c µ cm.…”

“…We shall come back to this point after analysing other materials. Now we move to CuMn alloys, employing the data from Mydosh et al [4,5], Cowen et al [6], and VS [7]. The experimental points correspond to samples with (nominally) only magnetic impurities (Mn).…”

“…A fundamental, and not yet fully solved problem is the dependence of T g on the composition of the alloy; i.e., how T g varies, as we change the concentrations (c, and c i ) of magnetic, and non magnetic impurities. Valuable experimental data have been collected by several researchers [3][4][5][6][7] ; yet, the observed behaviour is only partially understood. A primary question is: can we derive a formula that describes the experiments coherently, in a quantitative manner?…”

“…FIG.2:The freezing temperature T g in CuMn alloys vs concentration of Mn. Experimental data from[4][5][6][7] (black dots), and theoretical fit (solid line).…”