Magnetic phase transitions and magnetic entropy in the XY antiferromagnetic pyrochlores (Er1xYx)2Ti2O7

We present the results of experimental determination of the heat capacity of the pyrochlore Er₂Ti₂O₇ as a function of temperature (0.35-300 K) and magnetic field (up to 9 T), and for magnetically diluted solid solutions of the general formula (Er_1-x Y _x )₂Ti₂O₇ (x≤0.471). On either doping or increase of magnetic field, or both, the Néel temperature first shifts to lower temperature until a critical point above which there is no well-defined …