According to one embodiment, a magnetoresistive memory device includes: a first ferromagnetic layer; a stoichiometric first layer; a first insulator between the first ferromagnetic layer and the first layer; a second ferromagnetic layer between the first insulator and the first layer; and a non-stoichiometric second layer between the second ferromagnetic layer and the first layer. The second layer is in contact with the second ferromagnetic layer and the first layer.

A magnetic tunnel junction (MTJ) element is provided. The MTJ element includes a buffer layer, a seed layer disposed over the buffer layer, a reference layer disposed over the seed layer, a tunnel barrier layer disposed over the reference layer and a free layer disposed over the tunnel barrier layer. The seed layer includes a Cobalt (Co)-based film. The MTJ element in accordance with the present disclosure exhibits a low resistance desired for a low-power write operation, and a high TMR coefficient desired for a low bit-error-rate (BER) read operation.

A magnetic memory device including a magnetic tunnel junction (MTJ) pillar containing a stable resonant synthetic antiferromagnet (SAF) reference layered structure in which the ferromagnetic resonance characteristics of a polarizing magnetic layer of the SAF reference layered structure are substantially matched to at least a first magnetic reference layer within the SAF reference layered structure. By substantially matching the ferromagnetic resonance characteristics of the polarizing magnetic layer to at least the first magnetic reference layer, a MTJ pillar is provided in which the dynamic stability of the polarizing magnetic layer can be improved, and undesirable magnetic reference layer instability related write-errors can be mitigated.

Disclosed herein is a spin-orbit torque device including a lower ferromagnetic layer, a non-magnetic layer bonded to the lower ferromagnetic layer, and an upper ferromagnetic layer bonded to the non-magnetic layer, wherein a magnetization orientation of the lower ferromagnetic layer is randomly distributed. According to the present disclosure, it is possible to provide a magnetic memory device which cannot be physically duplicated and has reconfigurability using a spin-orbit torque.

The invention relates to a system comprising superparamagnetic or anhysteretic nanoparticles (NPs) functionalised with an antibody, and a thin-film-type substrate of metal or an oxide thereof, functionalised with the same antibody; and to a method for detecting a biological analyte, such as a cell, protein, microorganism or similar, preferably a pathogenic microorganism, and even more preferably Listeria. The method comprises: (a) obtaining a control signal from a substrate (magnetic or not) coated with a thin film of metal or an oxide thereof, preferably gold, which can be functionalised with an antibody, the control signal being a magnetoresistance signal, a total magnetisation signal or a signal of the magnetisation curve; (b) mixing superparamagnetic or anhysteretic NPs functionalised with the antibody, with a liquid sample to analyse and confirm the presence or absence of the biological analyte, the NPs and the liquid sample making contact for 10-90 minutes; (c) dripping the dispersion obtained in step (b) onto the substrate of step (a), and then washing to remove NPs that are not chemically anchored to the surface of the biological analyte; (d) leaving the substrate to dry and re-measuring a signal in the same way as carried out in step (a); and (e) counteracting the control signal obtained in step (a) and the signal obtained in step (d), and in the absence of differences between the two measurements, confirming the absence of the biological analyte in the sample, the amount of microorganisms being directly proportional to the signal measured.

The present invention is directed to a magnetic memory cell including a magnetic tunnel junction (MTJ) memory element and a two-terminal bidirectional selector coupled in series between two conductive lines. The MTJ memory element includes a magnetic free layer, a magnetic reference layer, and an insulating tunnel junction layer interposed therebetween. The two-terminal bidirectional selector includes bottom and top electrodes, first and third volatile switching layers interposed between the bottom and top electrodes, and a second volatile switching layer interposed between the first and third volatile switching layers. The bottom and top electrodes each independently include one of titanium nitride or iridium. The first and third volatile switching layers each include tantalum oxide and silver. The second volatile switching layer includes hafnium oxide and has a higher electrical resistance than the first and third volatile switching layers.

A memory device includes a perpendicular magnetic tunnel junction (pMTJ) stack, between a bottom electrode and a top electrode. In an embodiment, the pMTJ includes a fixed magnet, a tunnel barrier above the fixed magnet and a free magnet structure on the tunnel barrier. The free magnet structure includes a first free magnet on the tunnel barrier and a second free magnet above the first free magnet, wherein at least a portion of the free magnet proximal to an interface with the free magnet includes a transition metal. The free magnet structure having a transition metal between the first and the second free magnets advantageously improves the switching efficiency of the MTJ, while maintaining a thermal stability of at least 50 kT.

A magnet structure is a magnet structure for a TMR element which is an MR element. The magnet structure includes a bonded magnet compact that has a first main surface facing the TMR element, and a second main surface on a side opposite to the first main surface; and a tubular member that supports the bonded magnet compact. The bonded magnet compact has a gate portion which is provided on the second main surface and includes a gate mark formed by performing injection molding. The gate portion is provided at a position overlapping a center on the second main surface when seen from the second main surface side.

A magnetoresistive effect element includes a magnetization fixed layer, a magnetization free layer, and a non-magnetic spacer layer that is stacked between the magnetization fixed layer and the magnetization free layer. The magnetization free layer includes a first free layer and a second free layer that are formed of a ferromagnetic material, and a magnetic coupling layer that is stacked between the first free layer and the second free layer. The first free layer and the second free layer are magnetically coupled to each other by exchange coupling via the magnetic coupling layer such that magnetization directions of the first free layer and the second free layer are antiparallel to each other. The magnetic coupling layer is a non-magnetic layer that includes Ir and at least one of the following elements: Fe, Co and Ni.

Provided are a magnetoresistive element, a magnetic memory device, and a writing and reading method for a magnetic memory device, in which an aspect ratio of a junction portion can be decreased. A magnetoresistive element 1 of the invention, includes: a heavy metal layer 2 that is an epitaxial layer; and a junction portion 3 including a recording layer 31 that is provided on the heavy metal layer 2 and includes a ferromagnetic layer of an epitaxial layer magnetized in an in-plane direction, which is an epitaxial layer, a barrier layer 32 that is provided on the recording layer 31 and includes an insulating body, and a reference layer 33 that is provided on the barrier layer 32 and has magnetization fixed in the in-plane direction, in which the recording layer 31 is subjected to magnetization reversal by applying a write current to the heavy metal layer 2.