X-Ray Circular Magnetic Dichroism as a Probe of Spin Reorientation Transitions in Nd2Fe14B and Er2Fe2Fe14B

We present the first experimental observation of spin reorientation phase transitions (SRT) with the X-Ray Circular Magnetic Dichroism (XCMD) technique. The XCMD signal, related to the protection of the rare earth moment on the direction of the x-ray beam, has been measured as a function of temperature of both, a first-order SRT in Er2Fe14B (abrupt reorientation by 90 degrees) and a second-order one in Nd2Fe14B, (continuous tilt of the magnetization from the c-axis). The feasibility of this technique to study SRTs is demonstrated, resulting in a better understanding of the magnetic behavior of intermetallic compounds exhibiting coexistence of itinerant and localized magnetism.