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Multicomponent magnetic phase diagrams are a key property of functional materials for a variety of uses, such as manipulation of magnetization for energy efficient memory, data storage, and cooling applications. Strong spin-lattice coupling extends this functionality further by allowing electricfield-control of magnetization via strain coupling with a piezoelectric. Here this work explores the magnetic phase diagram of piezomagnetic Mn 3 NiN thin films, with a frustrated noncollinear antiferromagnetic (AFM) structure, as a function of the growth induced biaxial strain. Under compressive strain, the films support a canted AFM state with large coercivity of the transverse anomalous Hall resistivity, ρ xy , at low temperature, that transforms at a welldefined Néel transition temperature (T N ) into a soft ferrimagnetic-like (FIM) state at high temperatures. In stark contrast, under tensile strain, the low temperature canted AFM phase transitions to a state where ρ xy is an order of magnitude smaller and therefore consistent with a low magnetization phase. Neutron scattering confirms that the high temperature FIM-like phase of compressively strained films is magnetically ordered and the transition at T N is first-order. The results open the field toward future exploration of electricfield-driven piezospintronic and thin film caloric cooling applications in both Mn 3 NiN itself and the broader Mn 3 AN family.

Strontium molybdate (SrMoO3) thin films are grown epitaxially on strontium titanate (SrTiO3), magnesium oxide (MgO), and lanthanum aluminate (LaAlO3) substrates by pulsed laser deposition and possess electrical resistivity as low as 100 µΩ cm at room temperature. SrMoO3 is shown to have optical losses, characterized by the product of the Drude broadening, ΓD, and the square of the plasma frequency, ωpu2, significantly lower than TiN, though generally higher than Au. Also, it is demonstrated that there is a zero‐crossover wavelength of the real part of the dielectric permittivity, which is between 600 and 950 nm (2.05 and 1.31 eV), as measured by spectroscopic ellipsometry. Moreover, the epsilon near zero (ENZ) wavelength can be controlled by engineering the residual strain in the films, which arises from a strain dependence of the charge carrier concentration, as confirmed by density of states calculations. The relatively broad tunability of ENZ behavior observed in SrMoO3 demonstrates its potential suitability for transformation optics along with plasmonic applications in the visible to near infrared spectral range.

This paper presents an electrolytically gated broadband microwave sensor where atomically-thin graphene layers are integrated into coplanar waveguides and coupled with microfluidic channels. The interaction between a solution under test and the graphene surface causes material and concentrationspecific modifications of graphene's DC and AC conductivity. Moreover, wave propagation in the waveguide is modified by the dielectric properties of materials in its close proximity via the fringe field, resulting in a combined sensing mechanism leading to an enhanced S-parameter response compared to metallic microwave sensors. The possibility of further controlling the graphene conductivity via an electrolytic gate enables a new, multi-dimensional approach merging chemical field-effect sensing and microwave measurement methods. By controlling and synchronising frequency sweeps, electrochemical gating and liquid flow in the microfluidic channel, we generate multidimensional datasets that enable a thorough investigation of the solution under study. As proof of concept, we functionalise the graphene surface in order to identify specific single-stranded DNA sequences dispersed in phosphate buffered saline solution. We achieve a limit of detection concentration of ∼ 1 attomole per litre for a perfect match DNA strand and a sensitivity of ∼ 3 dB/decade for sub-pM concentrations. These results show that our devices represent a new and accurate metrological tool for chemical and biological sensing.

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