Magnetic properties of TbMn0.98Fe0.02O3 single crystal

Magnetic anisotropy, magnetization reversal and switching in Ni4Nb2O9 single crystals

“…In agreement with its peculiar magnetic ground state, Ni 4 Nb 2 O 9 exhibits unexpected characteristics, as (i) the same value of T comp whatever H applied along a or b, that is in contrast with the observations made on NdMn 0.8 Fe 0.2 O 3 single crystals, a ferrimagnet showing also MR [9] and (ii) similar values of θ p along the three directions, that clearly differ from Ni 2 Mo 3 O 8 , an antiferromagnet where Ni cations form also a honeycomb lattice [19]. Nevertheless, surprisingly, it seems that the conditions for observing MR vs H in the vicinity of T comp in Ni 4 Nb 2 O 9 are of the same order of magnitude as in other systems.…”

“…Furthermore, though a very small hysteresis loop is observed at 50 K, the loop is off centred (inset of figure 3(c)), which is characteristic of atomic exchange bias. The report of exchange bias in several compensated ferrimagnetic transition metal oxides supports this hypothesis, like in polycrystalline samples of CoCr 2 O 4 spinel [7,8] or in so-called rare-earth ferrimagnets like orthorhombic perovskites, such as single crystals of NdMn 0.8 Fe 0.2 O 3 [9], ErFeO 3 and GdCrO 3 [10], and SmFeO 3 [11]. Though additional measurements are necessary to go further, as done for crystals of ErFeO 3 orthoferrite [31], the competing antiferro-and ferro-magnetic interactions in Ni 4 Nb 2 O 9 crystal are supposed to produce exchange bias as in other compensated ferrimagnets [7][8][9][10][11].…”

“…Nevertheless, the rationalisation of the search for new compounds is not easy since negative magnetization may result from very different mechanisms [6] and since FIM occurs in different structures as spinels [1,7,8], perovskites [9][10][11], garnets [1] …. The common feature of all these compounds is that there is a site competition between several types of magnetic coupling, between two different cations occupying two different sites (as a transition metal and a lanthanide [11]) or between two sites occupied by the same element (as tetrahedra and octahedra in spinels [7,8]), which can also be influenced by disorder induced by substitution [7][8][9][10][11]. The competing magnetic interactions can also lead to interesting exchange bias and memory effects [7][8][9][10][11].…”

“…The common feature of all these compounds is that there is a site competition between several types of magnetic coupling, between two different cations occupying two different sites (as a transition metal and a lanthanide [11]) or between two sites occupied by the same element (as tetrahedra and octahedra in spinels [7,8]), which can also be influenced by disorder induced by substitution [7][8][9][10][11]. The competing magnetic interactions can also lead to interesting exchange bias and memory effects [7][8][9][10][11].…”

Understanding the magnetic dynamics and magnetostructural coupling in the paramagnetic phase ofTbMnO3by muon-spin spectroscopy

“…Growing was performed in air atmosphere; feed and seed rod were rotated with a speed of 30 rpm in opposite directions and a pulling speed of 6 mm/h was used. The typical length of a grown ingot was between 3 and 5 cm [17,18].…”