High Field Maganetization Process of Random Mixtures with Competing Exchange Interactions K2CuxA1-xF4(A=Mn and Co)

Abstract

The magnetization process of randomly mixed crystals K 2 Cu x A 1- x F 4 (A=Mn and Co) having ferromagnetic and antiferromagnetic competing interactions has been investigated in pulsed high magnetic fields. Three types of the magnetization curves in the ferromagnetic, spin-glass and antiferromagnetic regions, respectively, have been measured at 1.8 K in both systems. In K 2 Cu x Mn 1- x F 4 , the value of the exchange constant of Cu 2+ -Mn 2+ bonding in the ferromagnetic region is estimated to be -5±0.5 K from the analysis of the magnetization curve. The convex upward magnetization curve and the spin-flop transition have been observed in the spin-glass and antiferromagnetic regions, respectively. The magnetization curves of K 2 Cu x Co 1- x F 4 are compared with those of K 2 Cu x Mn 1- x F 4 to study the effect of the anisotropy on the magnetization process.