MAGNETIC-BEHAVIOR OF (CUIN)1-XMN2XTE2

Magnetic susceptibility measurements have been made on the chalcopyrit e diluted magnetic semiconductor (CuIn)1-xMn2xTe2 for concentrations 0 .01 less-than-or-equal-to x less-than-or-equal-to 0.101 and temperatur es 33 mK less-than-or-equal-to T less-than-or-equal-to 300 K. Samples with x>0.05 had similar values of the effective nearest-neighbor excha nge constant, with J(eff)/k(B)almost-equal-to - 18.5 K. The strength o f J(eff) fell sharply in samples with lower x, a characteristic not se en in wide band gap II-VI based alloys. Low-field ac susceptibility me asurements showed spin-glass behavior. Analysis of freezing temperatur e T(f) vs x data showed a possible crossover between different modes o f exchange, coincident with the sharp drop in J(eff). Preliminary carr ier concentration data suggests that the crossover may be driven by in creased numbers of free holes in some samples.