A permanent magnet including, at least once per group of ten consecutive ferromagnetic layers, a growth layer directly interposed between a top antiferromagnetic layer of a previous pattern and a bottom antiferromagnetic layer of a following pattern. This growth layer is entirely realized in a nonmagnetic material chosen from the group made up of the following metals: Ta, Cu, Ru, V, Mo, Hf, Mg, NiCr and NiFeCr, or it is realized by a stack of several sublayers of nonmagnetic material disposed immediately on one another, at least one of these sublayers being entirely realized in a material chosen from the group. The thickness of the growth layer is greater than 0.5 nm.

The present invention concerns, in particular, a method for obtaining a product with magnetocaloric effect from a single piece of material having a magnetic phase transition, the method comprising irradiation of at least one part of the material with ions, the irradiation being carried out with a suitable flux so that, after the irradiation, the material has various magnetic phase transition temperatures in the various parts of the material.

According to one embodiment, a sensor includes a film portion, one or more detectors fixed to the film portion, and a processor. The detector includes first and second detecting elements. The first detecting element includes a first magnetic layer. The second detecting element includes a second magnetic layer. A first change rate of a first signal is higher than a second change rate of the first signal. The first signal corresponds to a first electrical resistance of the first detecting element. A change rate of a second signal with respect to the change of the magnitude of the strain is higher than the second change rate. The second signal corresponds to a second electrical resistance of the second detecting element. The processor is configured to perform at least a first operation of outputting a second value. The second value is based on the second signal and a first value.

According to one embodiment, a sensor includes a film portion, one or more detectors fixed to the film portion, and a processor. The detector includes first and second detecting elements. The first detecting element includes a first magnetic layer. The second detecting element includes a second magnetic layer. A first change rate of a first signal is higher than a second change rate of the first signal. The first signal corresponds to a first electrical resistance of the first detecting element. A change rate of a second signal with respect to the change of the magnitude of the strain is higher than the second change rate. The second signal corresponds to a second electrical resistance of the second detecting element. The processor is configured to perform at least a first operation of outputting a second value. The second value is based on the second signal and a first value.

According to one embodiment, a sensor includes a supporter, a film portion, a first element, and a first magnetic portion. The supporter includes a first support portion and a second support portion. The film portion includes a first partial region supported by the first support portion. The first element is provided at the first partial region. The first element includes a first electrode region, a first opposing electrode region, and a first magnetic layer provided between the first electrode region and the first opposing electrode region. A direction from the second support portion toward the first magnetic portion is aligned with a first direction. The first direction is from the first opposing electrode region toward the first electrode region. At least a portion of the first magnetic portion overlaps at least a portion of the first element in a direction crossing the first direction.

The disclosure is directed to an iron-nitride material having a polycrystalline microstructure including a plurality of elongated crystallographic grains with grain boundaries, the iron-nitride material including at least one of an -Fe.sub.16N.sub.2 phase and a body-center-tetragonal (bct) phase comprising Fe and N. The disclosure is also directed a method producing an iron-nitride material. The method includes some combinations of preparing a raw material comprising iron, carrying out a microstructure build-up by annealing the prepared raw material at an elevated temperature and subsequently quenching the prepared raw material to produce a microstructure build-up material, annealing the microstructure build-up material, reducing the microstructure build-up material in a hydrogen environment, nitriding the reduced material to produce a nitrided material and subsequently quenching the nitrided material to a martensitic transformation temperature, stress annealing the nitrided material, and magnetic field annealing the stress-annealed material.

A permanent magnet includes at least two antiferromagnetic layers and at least two first ferromagnetic layers. A magnetization direction of each first ferromagnetic layer is set, by an exchange coupling, with one of the antiferromagnetic layers of the stack, parallel to and in the same direction as the magnetization directions of the other first ferromagnetic layers. The permanent magnet also includes at least one second ferromagnetic layer. A magnetization direction of each second ferromagnetic layer is pinned only by RKKY (Ruderman-Kittel-Kasuya-Yosida) coupling with at least one of the first ferromagnetic layers or with at least one other of the second ferromagnetic layers.

The disclosure is directed to an iron-nitride material having a polycrystalline microstructure including a plurality of elongated crystallographic grains with grain boundaries, the iron-nitride material including at least one of an ?-Fe.sub.16N.sub.2 phase and a body-center-tetragonal (bct) phase comprising Fe and N. The disclosure is also directed a method producing an iron-nitride material. The method includes some combinations of preparing a raw material comprising iron, carrying out a microstructure build-up by annealing the prepared raw material at an elevated temperature and subsequently quenching the prepared raw material to produce a microstructure build-up material, annealing the microstructure build-up material, reducing the microstructure build-up material in a hydrogen environment, nitriding the reduced material to produce a nitrided material and subsequently quenching the nitrided material to a martensitic transformation temperature, stress annealing the nitrided material, and magnetic field annealing the stress-annealed material.

A passive thermal switch device, for regulating a temperature of a thermal component configured to generate heat, includes a first plate and a second plate. The first plate is provided on the thermal component. The first plate includes a thermal switch material that switches from an antiferromagnetic state to a ferromagnetic state upon exceeding a state transition temperature. The second plate includes a permanent magnet. The second plate is moveable between a thermal insulator position and a thermal conductor position based on a temperature of the thermal switch material. In the thermal insulator position, the second plate is spaced apart from the first plate. In the thermal conductor position, the second plate is in contact with the first plate.

An optical sensor is disclosed. The optical sensor may include a substrate, a topological insulator layer formed on the substrate, an oxide layer formed on the topological insulator layer, a graphene layer stacked on the oxide layer, and a dielectric layer covering the graphene layer.