Prediction of a possible new intermediate spin ordering in holmium

Holmium exists in low-temperature conical and intermediate-temberature spiral magnetic phases, implying a temperature-dependent variation of effective anisotropy. We show that if this anisotropy is varied from the spiral to the conical region there will first be a second-order transition to an intermediate phase whose order is essentially a tilted spiral and then a first-order transition to the cone. The intermediate phase might be found at around 20 K.