Magnetic Structure of Mn3O4 by Neutron Diffraction

Abstract

Mn3O4 is a tetragonal spinel I41/amd. It is ferromagnetic below Tc = 43°K. At 4.2°K neutron diffraction measurements on powdered samples show the presence of 8 sublattices in a unit cell a, 2a, c which is double the chemical unit cell. These 8 sublattices are arranged as follows: 2 sublattices at tetrahedral sites and 6 sublattices at octahedral sites. At 4.2°K the moments are 4.65 μB on A sites and 3.55 μB on B sites with a resulting moment of 1.85 μB/molecule along the (010) direction. The study of thermal variation of the structure shows that at 33°K a rearrangement of moments occurs such that the chemical and magnetic unit cells become identical.

Synthesis, structure and magnetic properties ofβ-MnO 2 nanorods

“…The small magnetization coercivitiy of 0.9 kOe at 5 K of the b-MnO 2 nanorods (Fig. 4b) does not, however, support direct analogy with neither the c-Mn 2 O 3 nanoparticle-material nor the Mn 3 O 4 , which are both characterized by high coercivities of the order 8 kOe [16,17,19]. The FM spin structure within the investigated b-MnO 2 nanorods is obviously much softer.…”

“…Recent magnetic measurements on c-Mn 2 O 3 nanoparticles [16] have shown that the nanoparticle-material exhibits ferrimagnetism below T C = 39 K with high coercivity (~8 kOe at 5 K). Similarly, the Mn 3 O 4 bulk material (that is isostructural with c-Mn 2 O 3 ) was reported [17] to undergo a transition to a ferrimagnetic state at T C = 42 K. In another study [18], Mn 3 O 4 However, all the peaks in the x-ray spectrum of the nanorods in Fig. 2 can be indexed to the b-MnO 2 and a-Mn 2 O 3 phases and do not reveal the presence of any additional phase within the sensitivity of the XRD experiment (about 2% volume).…”

XRD and XPS characterization of mixed valence Mn3O4 hausmannite thin films prepared by chemical spray pyrolysis technique

“…Consequently, it is very important to control the growth conditions to obtain the expected Mn oxide. Bulk Mn 3 O 4 crystals have been studied well from both theoretical and experimental point of view [8][9][10]. Low-dimensional systems such as thin films, demonstrate a variety of physical, chemical, and functional properties different from those of the bulk materials due to their low-dimensionality and the quantum confinement effect.…”

Magnetic Properties of ZMTO Alloys

“…There are reports on ferrimagnetic phase transitions in Mn 3 O 4 and Mn 2 O 3 with transition temperatures 41-43 K [3] and 39 K [4], respectively. However those values, although close, are different from presented here.…”