اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدMagnetic Anisotropy and Orbital Ordering in Ca$_2$RuO$_4$
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We review the magnetic and orbital ordered states in cro{} by performing Resonant Elastic X-ray Scattering (REXS) at the Ru L$_{2,3}$-edges. In principle, the point symmetry at Ru sites does not constrain the direction of the magnetic moment below $T_N$. However early measurements reported the ordered moment entirely along the $vec{b}$ orthorhombic axis. Taking advantage of the large resonant enhancement of the magnetic scattering close to the Ru L$_2$ and L$_3$ absorption edges, we monitored the azimuthal, thermal and energy dependence of the REXS intensity and find that a canting ($m_c simeq 0.1 m_b$) along the $vec{c}$-orthorhombic axis is present. No signal was found for $m_a$ despite this component also being allowed by symmetry. Such findings are interpreted by a microscopic model Hamiltonian, and pose new constraints on the parameters describing the model. Using the same technique we reviewed the accepted orbital ordering picture. We detected no symmetry breaking associated with the signal increase at the so-called orbital ordering temperature ($simeq 260$ K). We did not find any changes of the orbital pattern even through the antiferromagnetic transition, suggesting that, if any, only a complex rearrangement of the orbitals, not directly measurable using linearly polarized light, can take place.
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Resonant x-ray diffraction performed at the $rm L_{II}$ and $rm L_{III}$ absorption edges of Ru has been used to investigate the magnetic and orbital ordering in Ca$_2$RuO$_4$ single crystals. A large resonant enhancement due to electric dipole $2pto
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