A polar corundum oxide displaying weak ferromagnetism at room temperature

Combining long-range magnetic order with polarity in the same structure is a prerequisite for the design of (magnetoelectric) multiferroic materials. There are now several demonstrated strategies to achieve this goal, but retaining magnetic order above room temperature remains a difficult target. Iron oxides in the +3 oxidation state have high magnetic ordering temperatures due to the size of the coupled moments. Here we prepare and characterize ScFeO(3) (SFO), which under pressure and in strain-stabilized thin films adopts a polar variant of the corundum structure, one of the archetypal binary oxide structures. Polar corundum ScFeO(3) has a weak ferromagnetic ground state below 356 K-this is in contrast to the purely antiferromagnetic ground state adopted by the well-studied ferroelectric BiFeO(3).     

Octupole vibrational states in the even-mass barium isotopes

A low-lying state of ^{132, 134, 136, 138}Ba, strongly excited in the scattering of 20 MeV α-particles at 175°, is identified as the first 3^? octupole vibrational state in each case. Angular distribution measurements for α-particle scattering to this state and the well-known first 2⁺ state in ^{132, 134, 136, 138}Ba are in agreement with harmonic-vibration coupled-channel predictions. Deformation parameters are obtained, and the deduced isoscalar transition rates are compared with measured electromagnetic transition rates. The first 3^? states of ^{132, 134, 136, 138}Ba are found to be at excitation energies of 2.070, 2.251, 2.529 and 2.879 MeV, respectively. A state in ¹³⁰Ba at an excitation energy of 1.948 MeV is tentatively identified as the first octupole-vibrational state in this nucleus.