Noncollinear magnetism in nanosized cobalt chromite

Using a combination of neutron diffraction with XYZ polarization analysis and magnetization measurements,
the noncollinear magnetism in nanosized cobalt chromite, a potential multiferroic material, is revealed. For
noninteracting 26.9(1) nm nanoparticles, a bulklike behavior is identified, including a ferrimagnetic Curie
temperature of 99 K and a transition to the spin spiral magnetic phase at 27 K with a temperature-dependent,
incommensurate propagation vector. A lock-in transition towards a commensurate propagation vector is not
observed. Much smaller, 3.1(2) nm, nanoparticles reveal a strong cluster glass behavior, characterized by
ferrimagnetic behavior below the Curie temperature of 43 K and a transition to asperomagnetic behavior at
18 K, with the absence of any magnetic reflections at a base temperature of 5 K.