Magnetic ordering in NdMn2O5 studied by the neutron diffraction

•The magnetic order in NdMn2O5 is non-commensurate at all temperatures of magnetic alignment.•The magnetic phase diagram of NdMn2O5is characterized by two coexisting propagation vectors k1=(0.5 0 kz1), k2=(0.5 0 kz2).•There are two reorientation transitions below TN=30 K.•The orientation of the magnetic helicoid has significant component along c-axis at all temperatures.

The magnetic ordering in NdMn2O5 single crystal has been studied by the neutron scattering, including XYZ-polarization analysis. At TN≈30 K the onset of the long-range magnetic order with incommensurate wave vector k=(0.5 0 ~0.36) is observed. Below 30 K two magnetic phases are observed with propagation vectors close to each other: k1=(0.5 0 kz1), k2=(0.5 0 kz2). kz1, kz2 components increase monotonously with temperature decrease down to 25 K, then remain to be constant with values kz1=0.384(2), kz2=0.395(2). Two reorientation transitions were observed at ~20 K and at ~5 K.