University of Minnesota

Carnegie Mellon University

Delin Zhang

Jian-Ping Wang

Yanfeng Jiang

Bin Ma

Jinming Liu

Sara A Majetich

Md Aminul Mehedi

Protyush Sahu

Mukund Bapna

Thomas Peterson

Yiming Wu

Fan Zhang

Anthony William Hurben

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 α″-FeNphase 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.

Iron-rich permanent magnet

An example composition may include a plurality of grains including an iron nitride phase. The plurality of grains may have an average grain size between about 10 nm and about 200 nm. An example technique may include treating a composition including a plurality of grains including an iron-based phase to adjust an average grain size of the plurality of grains to between about 20 nm and about 100 nm. The example technique may include nitriding the plurality of grains to form or grow an iron nitride phase.

Iron nitride compositions

A magnetic device includes a layer stack comprising a first ferromagnetic layer; a spacer layer on the first ferromagnetic layer; a second ferromagnetic layer on the spacer layer; a dielectric barrier layer on the second ferromagnetic layer; an insertion layer positioned between the second ferromagnetic layer and the dielectric barrier layer; and a fixed layer or an electrode on the dielectric barrier layer. In some examples, a magnetic orientation of the second ferromagnetic layer is switched by a bias voltage across the layer stack without application of an external magnetic field; an antiferromagnetic coupling of the first and second ferromagnetic layers is increased by the bias voltage applying a negative charge to the fixed layer or the electrode, and the antiferromagnetic coupling of the first and second ferromagnetic layers is decreased by the bias voltage applying a positive charge to the fixed layer or the electrode.

Electric field switchable magnetic devices

A magnetic device may include a layer stack including a work function structure, a dielectric layer, and a ferromagnetic layer, where the ferromagnetic layer is positioned between the work function structure and the dielectric layer. The work function structure is configured to deplete electrons from the ferromagnetic layer or accumulate electrons in the ferromagnetic layer. A magnetization orientation of the ferromagnetic layer is configured to be switched by a voltage applied across the layer stack or by a voltage applied across or through the work function structure.

Work function structure for voltage-controlled magnetic anisotropy

A magnetic device may include a layer stack. The layer stack may include a first ferromagnetic layer; a spacer layer on the first ferromagnetic layer; a second ferromagnetic layer on the spacer layer; and a dielectric barrier layer on the second ferromagnetic layer. In some examples, the layer stack may also include an additional ferromagnetic layer and an additional spacer layer. The magnetic device also may include a voltage source configured to apply a bias voltage across the layer stack to cause switching of a magnetic orientation of the second ferromagnetic layer without application of an external magnetic field.

A magnetic device may include a layer stack. The layer stack may include a first ferromagnetic layer; a non-magnetic spacer layer on the first ferromagnetic layer, where the non-magnetic spacer layer comprises at least one of Ru, Ir, Ta, Cr, W, Mo, Re, Hf, Zr, or V; a second ferromagnetic layer on the non-magnetic spacer layer; and an oxide layer on the second ferromagnetic layer. The magnetic device also may include a voltage source configured to apply a bias voltage across the layer stack to cause switching of a magnetic orientation of the second ferromagnetic layer without application of an external magnetic field or a current. A thickness and composition of the non-magnetic spacer layer may be selected to enable a switching direction of the magnetic orientation of the second ferromagnetic layer to be controlled by a sign of the bias voltage.

Articles including a fixing layer and a free layer including a layer including an FePd alloy. The free layer may include a composite layer including a perpendicular synthetic antiferromagnetic (p-SAF) structure. Techniques for forming and using articles including FePd alloy layers or p-SAF structures. Example articles and techniques may be usable for storage and logic devices.

Growing community of inventors

Saint Paul, MN, United States of America

Delin Zhang