Voltage- and temperature-dependent rare-earth dopant contribution to the interfacial magnetic anisotropy

In-plane Néel wall chirality and orientation of interfacial Dzyaloshinskii-Moriya vector in magnetic films

The interfacial Dzyaloshinskii-Moriya interaction (DMI) is of great interest as it can stabilize chiral spin structures in thin films. Experiments verifying the orientation of the interfacial DMI vector remain rare, in part due to the difficulty of separating vector components of DMI. In this study, Fe/Ni bilayers and Co/Ni multilayers were deposited epitaxially onto Cu(001) and Pt(111) substrates, respectively. By tailoring the effective anisotropy, spin reorientation transitions (SRTs) are employed to probe the orientation of the DMI vector by measuring the spin structure of domain walls on …

Low-energy Structural Dynamics of Ferroelectric Domain Walls in Hexagonal Rare-earth Manganites

Domain walls (DWs) in ferroic materials, across which the order parameter abruptly changes its orientation, can host emergent properties that are absent in the bulk domains. Using a broadband ($10^6-10^{10}$ Hz) scanning impedance microscope, we show that the electrical response of the interlocked antiphase boundaries and ferroelectric domain walls in hexagonal rare-earth manganites ($h-RMnO_3$) is dominated by the bound-charge oscillation rather than free-carrier conduction at the DWs. As a measure of the rate of energy dissipation, the effective conductivity of DWs on the (001) surfaces of $…

Interfacial Thermal Transport in Boron Nitride-Polymer Nanocomposite

Polymer composites with thermally conductive nanoscale filler particles, such as graphene and hexagonal boron nitride (h-BN), are promising for certain heat transfer applications. While graphene-polymer composites have been extensively investigated, studies on h-BN-polymer composites has been relatively rare. In this paper, we use molecular dynamics (MD) simulations to study the interfacial thermal conductance (ITC) involved in the h-BN-polymer composites. We first compare the ITC across h-BN/hexane (C6H14) interfaces to that of graphene/hexane interfaces, where we found that the electrostatic…

Protecting a diamond quantum memory by charge state control

In recent years, solid-state spin systems have emerged as promising candidates for quantum information processing (QIP). Prominent examples are the Nitrogen-Vacancy (NV) center in diamond, phosphorous dopants in silicon (Si:P), rare-earth ions in solids and V$_{\text{Si}}$-centers in Silicon-carbide (SiC). The Si:P system has demonstrated, that by eliminating the electron spin of the dopant, its nuclear spins can yield exceedingly long spin coherence times. For NV centers, however, a proper charge state for storage of nuclear spin qubit coherence has not been identified yet. Here, we identify …

Optical dependence of electrically-detected magnetic resonance in lightly-doped Si:P devices

Electrically-detected magnetic resonance (EDMR) provides a highly sensitive method for reading out the state of donor spins in silicon. The technique relies on a spin-dependent recombination (SDR) process involving dopant spins that are coupled to interfacial defect spins near the Si/SiO$_2$ interface. To prevent ionization of the donors, the experiments are performed at cryogenic temperatures and the mobile charge carriers needed are generated via optical excitation. The influence of this optical excitation on the SDR process and the resulting EDMR signal is still not well understood. Here, w…

稀土原子在混合金属-有机界面的各向异性与反铁磁交换耦合中的作用

The role of rare-earth atoms in the anisotropy and antiferromagnetic exchange coupling at a hybrid metal-organic interface

本研究探讨了4f稀土原子在CuPc/REAu2混合金属-有机界面中对磁各向异性及反铁磁交换耦合的作用，发现HoAu2可增强面外各向异性，且未淬灭轨道角动量的稀土原子能诱导各向异性界面交换耦合。

Difference between thermo- and pyroelectric Co- based RE-(= Nd, Y, Gd, Ce)-oxide composites measured by high-temperature gradient

Seebeck-Voltage measurements of Cobalt-based oxide-composites containing rare-earth elements (RE= Nd, Y, Gd, Ce) were performed under high temperature gradients up to 700 K. Several dependences were measured, Seebeeck voltage as a function of time U_S(t)or temperature difference U_S(Delta_T), closed circuited electric current as a function of Seebeck voltage I_S(U_S), or time I_S(t). While Nd2O3+CoO and Y2O3+CoO show linear n-type US(t)-behavior as usual thermoelectrics, Gd2O3+CoO possesses a large hysteresis. At both, Gd2O3- and Ce2O3+CoO also large time dependence I(t) referred to as pyroele…