Modulated ferromagnetic ordering and the magnetocaloric response of Eu4PdMg

Neutron powder diffraction confirms that the primary ordering mode in Eu4PdMg is ferromagnetic with a europium moment of 6.5(2) mu(B). Eu-151 Mossbauer spectroscopy shows that the unusual linear temperature dependence of the magnetisation reported for this system is an intrinsic property and not an artefact of the applied field. The form and temperature evolution of the Eu-151 Mossbauer spectra strongly suggest that there is an incommensurate modulation to the magnetic structure that modifies the basic ferromagnetic order. This modulated structure may be the origin of the broad magnetocaloric response previously observed in Eu4PdMg. (c) 2015 AIP Publishing LLC.