Canted Magnetic Ground State Of Quarterdoped Manganites R0.75ca0.25mno3 (R = Y, Tb, Dy, Ho, And Er)

Polycrystalline samples of the quarter-doped manganites R0.75Ca0.25MnO3 (R Y, Tb, Dy, Ho, and Er) were studied by x-ray diffraction and AC/DC susceptibility measurements. All five samples are orthorhombic and exhibit similar magnetic properties: enhanced ferromagnetism below T1 (similar to 80 K) and a spin glass (SG) state below TSG (similar to 30 K). With increasing R3+ ionic size, both T1 and TSG generally increase. The single crystal neutron diffraction results on Tb0.75Ca0.25MnO3 revealed that the SG state is mainly composed of a short-range ordered version of a novel canted (i. e. noncollinear) antiferromagnetic spin state. Furthermore, calculations based on the double exchange model for quarter-doped manganites reveal that this new magnetic phase provides a transition state between the ferromagnetic state and the theoretically predicted spin-orthogonal stripe phase.