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We investigated the magnetic characteristics of Na

We investigated the magnetic characteristics of Na2Co2TeO6 at different temperatures and magnetic field. The experimental results indicated that the magnetic field can disturb the antiferromagnetic interaction and lead to the disorder. Magnetization curves measured with different angles θ (θ is between the magnetic field direction and c axis) express the magnetocrystalline anisotropy in this system. When the angle θ = 0 (magnetic field parallel to c axis), two continuous magnetic phase transitions at critical temperature T N1 and T N3 were observed. As θ changes, T N1 is almost independent on θ, indicating the magnetic ordering at T N1 was a spontaneous behavior with a robust AFM characteristic. On the other hand, as θ increases from 0 to 180, T N3 presents extreme value at θ = 90 (magnetic field perpendicular to c axis). It indicates that T N3 were sensitive to temperature and magnetic fields. At some angles closing to ab plane, an additional phase transition was observed at T N2. This phase transition at T N2 may mainly result from the long range antiferromagnetic ordering within ab-plane. Furthermore, the magnetization measurement up to 50 T revealed the strong antiferromagnetic coupling in the system, and in which the magnetic coupling within the honeycomb layers is strong and the magnetic coupling interaction between honeycomb layers is weaker. Based on the experimental results, we have obtained the complete magnetic phase diagram.

A new two-dimensional (2D) fluorophosphate compound Na

We report the study of a triaxial vector magnetoresistance (MR) in nonmagnetic (Bi

We report the study of a tri-axial vector magnetoresistance (MR) in nonmagnetic (Bi1-xInx)2Se3 nanodevices at the composition of x = 0.08. We show a dumbbell-shaped in-plane negative MR up to room temperature as well as a large out-of-plane positive MR. MR at three directions is about in a -3%: -1%: 225% ratio at 2 K. Through both the thickness and composition-dependent magnetotransport measurements, we show that the in-plane negative MR is due to the topological phase transition enhanced intersurface coupling near the topological critical point. Our devices suggest the great potential for room-temperature spintronic applications, for example, vector magnetic sensors., Comment: 23 pages, 12 figures