Hall voltage measurements in RE-TM/X multilayered films

The authors studied the properties of magnetron-sputtered multilayered films of amorphous rare-earth-transition-metal (RE-TM) layers separated by interlayers of X (where X was W, Pt, Co, or PtCo) by plotting hysteresis loops of the extraordinary Hall voltage as a function of the applied field. The low impedance of the interlayers means that shorting and shunting effects will reduce the measured Hall voltage in a multilayered film, V_H^m, from that actually generated in the RE-TM layers, V_H. The authors derived an expression for the reduced V_H^m expected as a consequence of these effects. Comparison with experimental data showed that the reduced Hall voltage in a multilayer was consistent with these shorting effects and was not changed in any more fundamental manner from that generated in a plain RE-TM film of the same composition and total thickness. This is in contrast with other magnetic properties, such as the coercivity, which can be fundamentally changed by making RE-TM/X multilayered structures