Hall effect anomalies at the magnetic phase transitions in MnAs1-xPxcompounds

Abstract

The specific Hall resistivity rho H of MnAs1-xPx crystals (x=0.1, 0.123) has been measured at stationary conditions for temperatures between 50 and 250K using the double-AC method with Bpeak<or=0.4 T. The combination of experimentally determined magnetisation values with the isothermal curves rho H(B) allowed for the separation of the normal and anomalous Hall constants R0 and RS, which show different anomalies at the phase transition temperatures TN, Tl and Tk. The dependences on R0(T) are interpreted in terms of a two-band model leading to the concept of charge-carrier localisation at Tk i.e. at the low-temperature magnetic phase transition beta to or from gamma .