Shipeng Shen

Observation of Resonant Quantum Magnetoelectric Effect in a Multiferroic Metal-Organic Framework.

A resonant quantum magnetoelectric coupling effect has been demonstrated in the multiferroic metal-organic framework of [(CH3)2NH2]Fe(HCOO)3. This material shows a coexistence of a spin-canted antiferromagnetic order and ferroelectricity as well as clear magnetoelectric coupling below TN ≈ 19 K. In addition, a component of single-ion quantum magnets develops below ∼ 8 K because of an intrinsic magnetic phase separation. The stair-shaped magnetic hysteresis loop at 2 K signals resonant quantum tunneling of magnetization. Meanwhile, the magnetic field dependence of dielectric permittivity exhibits sharp peaks just at the critical tunneling fields, evidencing the occurrence of resonant quantum magnetoelectric coupling effect. This resonant effect enables a simple electrical detection of quantum tunneling of magnetization.

Carrier concentration and mobility in GaN epilayers on sapphire substrate studied by infrared reflection spectroscopy

We report the measurement of carrier concentration and mobility of metalorganic chemical vapor deposited GaN thin films on the sapphire substrate by an infrared reflection technique. By fitting with the experimental data we obtain all the parameters of the lattice vibration oscillators and of the plasmon. From the plasmon frequency and the damping constant we have derived the carrier concentration and the electron mobility. The concentration agrees with the Hall data very well while the mobility values are smaller than that of the Hall measurement by a factor of about 0.5. We attribute such mobility lowering to the increase of scattering for the electrons coupling with the incident photons.

Magnetic-ion-induced displacive electric polarization inFeO5bipyramidal units of(Ba,Sr)Fe12O19hexaferrites

Electric polarization in conventional ferroelectric oxides usually involves nonmagnetic transition-metal ions with an empty d shell (the d

Uniaxial ferroelectric quantum criticality in multiferroic hexaferrites BaFe12O19 and SrFe12O19.

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Magnetic field reversal of electric polarization and magnetoelectric phase diagram of the hexaferrite Ba1.3Sr0.7Co0.9Zn1.1Fe10.8Al1.2O22

rule). Here we unravel a new mechanism for local electric dipoles based on magnetic Fe

Quantum electric-dipole liquid on a triangular lattice.

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Nonvolatile Memory Based on Nonlinear Magnetoelectric Effects

(3d

High electron mobility and large magnetoresistance in the half-Heusler semimetal LuPtBi

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Nonvolatile electric-field control of magnetization in a Y-type hexaferrite

) ion violating the d

Proximity effect between a topological insulator and a magnetic insulator with large perpendicular anisotropy

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