Magnetic order in the pseudogap phase of HgBa2CuO4+δstudied by spin-polarized neutron diffraction

Abstract

(2008)], this establishes the universal existence of a genuine novel magnetic phase in underdoped cuprates with high maximal Tc (above 90 K at optimal doping). Here we report a systematic study of an underdoped Hg1201 sample (Tc = 75 K), the result of which is consistent with the previously established doping dependence of the magnetic signal. We present an assumption-free analysis of all the data available for Hg1201. Depending on how the hole concentration is estimated, comparison with the results for YBCO leads to different competition scenarios between the q = 0 magnetic order and the spin-density-wave order found in heavily underdoped YBCO.

Normal state pair nematicity and hidden magnetic order and metal-insulator (fermionboson) crossover origin of pseudogap phase of cuprates II

“…While their evolution with doping (see Refs. [28][29][30]) qualitatively coincides with that of the NRs, described in [3]. However, minimal size NRs are single bosons, therefore, the IUC hidden magnetic order objects are also single bosons and PG and HTS pairs.…”

“…First observed in YBa 2 Cu 3 O 6+x (Y123) compound, using polarized elastic neutron diffraction [28], the hidden magnetic order has been observed in three other copper-oxide families: HgBa 2 CuO 4+δ (Hg1201) [29,30], La 2−x Sr x CuO 4 (La214) [31] and Bi 2 Sr 2 CaCu 2 O 8+δ (Bi-2212) [32] (see for references also [33]). Since the size of detection was a few structural cells, it was called the intra-unit-cell (IUC) hidden magnetic order.…”

Absence of Static Loop-Current Magnetism at the Apical Oxygen Site inHgBa2CuO4+δfrom NMR

“…[47,48] Roughly speaking these are 10 −11 s for neutrons,[8] 10 −8 s for µSR, [15] and 10 −6 for NMR frequency shifts. In the context of Hg1201 this was noted by Li et al [12] In summary, we have measured the temperature, field, and angular dependence of the narrow planar and apical 17 O NMR spectra in an underdoped Hg1201 single crystal. There are no indications of static magnetic fields from circulating orbital currents proposed theoretically, within our accuracy of 0.4 G. The apical oxygen spectra have a small temperature dependence above T c which has axial symmetry, consistent with a direct dipolar field from the Cu +2 site.…”

“…Polarized neutron scattering in YBa 2 Cu 3 O 7−δ [8][9][10], HgBa 2 CuO 4+δ (Hg1201) [11,12], Bi 2 Sr 2 CaCu 2 O 8+δ [13], and La 2−x Sr x CuO 4 (short ranged) [14] show the appearance of broken time reversal symmetry that correlates with the onset of the pseudogap phase with a magnetic moment tilted away from the crystalline c-axis. A muon spin relaxation (µSR) experiment in zero field was unable to detect this magnetism [15] although screening effects may account for muon insensitivity.…”

dc Josephson Current Between an Isotropic and a d-Wave or Extended s-Wave Partially Gapped Charge Density Wave Superconductor

“…Nevertheless, the type of order parameter competing with Cooper pairing in cuprates is not known with certainty. For instance, neutron diffraction studies of a number of various high-T c oxides revealed a nonhomogeneous magnetic ordering (usually associated with SDWs) in the pseudogap state [208,209].…”