Manipulating4fquadrupolar pair-interactions inTbB2C2using a magnetic field

Abstract

Resonant soft-x-ray Bragg diffraction at the Tb M 4,5 edges and nonresonant Bragg diffraction have been used to investigate orbitals in TbB 2 C 2 . The Tb 4f quadrupole moments are ordered in zero field below T N and show a ferroquadrupolar alignment dictated by the antiferromagnetic order. With increasing applied field along ͓110͔, the Tb 4f magnetic dipole moments rotate in a gradual manner toward the field. The quadrupole moment is rigidly coupled to the magnetic moment and follows this field-induced rotation. The quadrupolar pairinteraction is found to depend on the specific orientation of the orbitals as predicted theoretically and can be manipulated with an applied magnetic field.

Resonant elastic soft x-ray scattering

“…Here, the shielding of the 4f shell by the outer 5d electrons causes a weaker coupling of the electronic degrees of freedom of the 4f electrons to the lattice and hence, allows studying orbital order mechanisms in a less complex situation. In a series of publications on orbital ordering of 4f electrons in REB 2 C 2 compounds Mulders et al could show that RSXS performed at the RE −M 4,5 resonances is not just able to observe orbital order of the 4f electrons but can in addition quantify the contributions of the different higher order multipole moments to the electronic ordering [219,220,221,222].…”

Resonant X-ray Scattering Experiments on the Ordering of Electronic Degrees of Freedom

“…[95][96][97][98][99] In TbB 2 C 2 , an AFMordered state is realized, where the z ¼ 0 sheet shown in Fig. 18 is antiferromagnetically stacked along the c-axis without the 90 rotation as in DyB 2 C 2 .…”

“…This change is clearly demonstrated by the RXS experiment in magnetic fields. 96,97) 6 : observation of aspherical charge distribution by Thomson scattering CeB 6 is one of the most well known f electron compounds that has attracted researchers for more than 30 years because of its mysterious ordered phase. Now, the AFQ order has been established by various experimental and theoretical studies.…”

“…90,97,98) The advantage of M-edge RXS is that the f orbital is directly probed by the fundamental E1 resonance. Furthermore, resonance enhancement is much larger than that in L-edge RXS because the overlap between the 3d and 4f orbitals is much larger than that between the 2p and 5d orbitals.…”

RASOR: An advanced instrument for soft x-ray reflectivity and diffraction

“…31,32 Following these early results, soft x-ray diffraction has been used to study many more materials, not only transition metal oxides such as cuprates, [33][34][35] nickelates, 36,37 and cobaltates, 38 but has also been a powerful tool in deciphering the magnetic structure of complex rare earth materials. [39][40][41] A recent, highly successful, experimental focus using soft x-ray diffraction has been to study multiferroic materials, including the RMn 2 O 5 ͑Refs. 42-44͒ and RMnO 3 ͑Refs.…”