The effect of Er doping on the spin reorientation transition in Ho1−xErxAl2

► First order spin reorientation transition in Ho1−xErxAl2: effect of Er doping. ► The temperature of the first order transition remains practically unaffected. ► The Curie temperature shifts to higher temperatures with increasing Er. ► The 4f charge densities of Ho3+ and Er3+ responsible for the observed behavior. ► The easy magnetization directions of HoAl2 and ErAl2 also hold accountable.