Weak ferromagnetic spin and charge stripe order inLa5∕3Sr1∕3NiO4

Abstract

We present magnetisation and specific heat data of a La 5/3 Sr 1/3 NiO4 single crystal in high magnetic fields. From the charge and spin stripe ordering temperatures, as well as a magnetic low temperature transition, we have constructed the electronic phase diagram for fields up to 14 Tesla. While the charge stripe ordering temperature TCO is independent of the magnetic field, there is a significant shift of the spin stripe ordering temperature TSO of about 1.5 K/Tesla, if the magnetic fields is applied parallel to the NiO2-planes. The specific heat measurements indicate a large anomalous entropy change at TCO. In contrast, no significant entropy change is observed at the spin stripe transition. The high field magnetisation experiments reveal the presence of in-plane weak ferromagnetic moments in the charge stripe ordered phase. From a phenomenological analysis, the magnetic correlation length of these moments is determined. We suggest that the weak ferromagnetism is due either to the presence of bond-centered charge stripes or to double exchange interactions across site-centered charge stripes.

Stacked charge stripes in the quasi-2D trilayer nickelate La 4 Ni 3 O 8

“…We also find similar signatures in transport, magnetic, and thermodynamic data measured on La-438 crystals as those reported in the unambiguously identified charge stripe phase LSNO-1/3 (7,16,27,49). Fig.…”

“…The magnetic susceptibility (Fig. 1B) shows a step at 105 K, which is again qualitatively similar to that observed in LSNO-1/3 (49). Although LSNO-1/3 shows a slope change in dχ/dT at T SO ∼ 194 K < T CO ∼ 239 K (49), we find no evidence for such in La-438 below 105 K. It is possible that La-438 does not have such a spin ordering transition or that it is coincident with the localization transition at 105 K. A Curie-Weiss analysis of the high-temperature data can be found in SI Text, Magnetization and Figs.…”

“…C p /T is independent of the magnetic field up to 9 T within the experimental resolution (SI Text, Heat Capacity and Fig. S3), a behavior similar to that reported for LSNO-1/3 (49). The λ-like shape of the anomaly in C p (Fig.…”

“…1C, Inset) and the absence of thermal hysteresis in the magnetic susceptibility (Fig. 1B, Inset) evidence a second-order phase transition, as was reported for charge stripe formation in LSNO-1/3 (49). To estimate the entropy change of the transition, we have phenomenologically fit the behavior above and below with a fifth-order polynomial and subtracted this background (SI Text, Heat Capacity).…”

Charge order, dielectric response, and local structure of La5/3Sr1/3NiO4 system

“…Among the TMOs, the La 2-x Sr x NiO 4 , popularly called nickelates, construct good example of such systems with complex interplay between spin-charge-lattice degrees of freedom [5][6][7][8][9][10][11][12][13][14][15][16] . The nickelates have been studied intensively, however, a substantial amount of work is dedicated to the La 5/3 Sr 1/3 NiO 4 , merely due to the fact that the system appears with robust charge stripe ordering for this doping, making it a suitable system to address various functions of the TMO perovskites.…”