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In this study an extended low energy phase diagram for NaxCoO2 is experimentally established with emphasis on the high x range. It is based on systematic heat capacity studies on both polycrystalline and single crystalline samples and on uSR measurements. Main features are the existence of mass enhancement, spin fluctuations without long-range order, and magnetic order with associated Fermi surface gapping. The latter is seen in the electronic density of states (DOS) and suppression of nuclear specific heat. While there is agreement between the band structure and the low energy DOS in the low x range, in the high x range (x > 0.6) the thermodynamically determined DOS is approximately three times that deduced from the angle-resolved photoemission spectroscopy (ARPES)-measured band dispersion or local-density approximation (LDA) calculations.
We present bulk and neutron scattering measurements performed on the isotopically enriched $^{154}mathrm{Sm_2Ti_2O_7}$ and $^{154}mathrm{Sm_2Sn_2O_7}$ samples. Both compounds display sharp heat capacity anomalies, at 350 mK and 440 mK, respectively.
The quantum spin systems Cu$_2$MBO$_5$ (M = Al, Ga) with the ludwigite crystal structure consist of a structurally ordered Cu$^{2+}$ sublattice in the form of three-leg ladders, interpenetrated by a structurally disordered sublattice with a statistic
The $4f$-electron system YbAl$_3$C$_3$ with a non-magnetic spin-dimer ground state has been studied by neutron diffraction in an applied magnetic field. A long-range magnetic order involving both ferromagnetic and antiferromagnetic components has bee
We performed ultrafast time-resolved near-infrared pump, resonant soft X-ray diffraction probe measurements to investigate the coupling between the photoexcited electronic system and the spin cycloid magnetic order in multiferroic TbMnO3 at low tempe
The magnetic properties of the layered oxypnictide LaMnAsO have been revisited using neutron scattering and magnetization measurements. The present measurements identify the N{e}el temperature $T_N$ = 360(1) K. Below $T_N$ the critical exponent descr