# US 2021/0280772 A1 · Spin transistors based on voltage-controlled magnon transport in multiferroic antiferromagnets

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- Number: US 2021/0280772 A1
- Document ID: US20210280772A1
- Status: Published application
- Kind: A1
- Application number: 16/809,970
- Filed: 2020-03-05
- Published: 2021-09-09
- Earliest claimed: 2020-03-05
- Assignees: Wisconsin Alumni Research Foundation
- Applicants: Wisconsin Alumni Research Foundation
- Inventors: Chang-Beom EOM; Tianxiang NAN; Jonathon SCHAD
- Web page: https://patentgrep.com/patent/US20210280772A1

## CPC

- B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
- H10D 48/385: {Devices using spin-polarised carriers}
- G01R 33/1284: {Spin resolved measurements; Influencing spins during measurements, e.g. in spintronics devices}
- H10D 62/80: characterised by the materials
- H10N 50/20: Spin-polarised current-controlled devices (magnetoresistive devices H10N50/10)
- G01R 33/1292: {Measuring domain wall position or domain wall motion}
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

Voltage-controlled spin field effect transistors (“spin transistors”) and methods for their use in switching applications are provided. In the spin transistors, spin current is transported from a spin injection contact to a spin detection contact through a multiferroic antiferromagnetic channel via magnon propagation. The spin current transport is modulated by the application of a gate voltage that increases the number of domain boundaries the multiferroic antiferromagnetic material.

## Claims

### Claim 1

A voltage-controlled spin transistor comprising:
a spin injector contact;
a spin detector contact;
a layer of a multiferroic material that forms a channel between the spin injector contact and the spin detector contact;
at least one top gate contact; and
at least one bottom gate contact,
wherein the at least one top gate contact and the at least one bottom gate contact are configured to apply a gate voltage across the channel.

### Claim 2 (depends on 1)

The spin transistor of claim 1, wherein the multiferroic material is a monodomain multiferroic material.

### Claim 3 (depends on 1)

The spin transistor of claim 1, wherein the multiferroic material is BiFeO3.

### Claim 4 (depends on 3)

The spin transistor of claim 3, wherein the BiFeO3 is (001)-oriented BiFeO3.

### Claim 5 (depends on 3)

The spin transistor of claim 3, wherein the BiFeO3 is (111)-oriented BiFeO3.

### Claim 6 (depends on 3)

The spin transistor of claim 3, wherein the BiFeO3 is monodomain multiferroic BiFeO3.

### Claim 7 (depends on 1)

The spin transistor of claim 1, wherein the top gate contact and the bottom gate contact comprise a heavy metal, a two-dimensional electron gas, a 4d transition metal oxide, a 5d transition metal oxide, or a topological insulator.

### Claim 8 (depends on 1)

The spin transistor of claim 1, wherein the bottom gate contact comprises an electrically conductive perovskite oxide.

### Claim 9 (depends on 6)

The spin transistor of claim 6, wherein the bottom gate contact comprises SrRuO3 or LaSrMO3 and the top gate contact comprises a metal.

### Claim 10 (depends on 9)

The spin transistor of claim 9, wherein the bottom gate contact comprises SrRuO3 and the top gate electrode comprises a heavy metal.

### Claim 11

A method of operating the spin transistor comprising:
a spin injector contact;
a spin detector contact;
a layer of a multiferroic material that forms a channel between the spin injector contact and the spin detector contact;
at least one top gate contact; and
at least one bottom gate contact,
wherein the at least one top gate contact and the at least one bottom gate contact are configured to apply a gate voltage across the channel, the method comprising:
creating a spin current in the spin injector contact, whereby the spin current is injected into the channel and transported through the channel to the spin detector contact via magnon propagation; and
applying a gate voltage across the channel, wherein the application of the gate voltages increases the density of domain boundaries in the channel and attenuates spin current transport through the channel.

### Claim 12 (depends on 11)

The method of claim 11, wherein the multiferroic material is a monodomain multiferroic material prior to the application of the gate voltage.

### Claim 13 (depends on 11)

The method of claim 11, wherein the multiferroic material is BiFeO3.

### Claim 14 (depends on 13)

The method of claim 13, wherein the BiFeO3 is (001)-oriented BiFeO3.

### Claim 15 (depends on 13)

The method of claim 13, wherein the BiFeO3 is (111)-oriented BiFeO3.

### Claim 16 (depends on 13)

The method of claim 13, wherein the BiFeO3 is monodomain multiferroic BiFeO3.

### Claim 17 (depends on 11)

The method of claim 11, wherein the top gate contact and the bottom gate contact comprise a heavy metal, a two-dimensional electron gas, a 4d transition metal oxide, a 5d transition metal oxide, or a topological insulator.

### Claim 18 (depends on 11)

The method of claim 11, wherein the bottom gate contact comprises an electrically conductive perovskite oxide.

### Claim 19 (depends on 16)

The method of claim 16, wherein the bottom gate contact comprises SrRuO3 or LaSrMO3 and the top gate contact comprises a metal.

### Claim 20 (depends on 19)

The method of claim 19, wherein the bottom gate contact comprises SrRuO3 and the top gate electrode comprises a heavy metal.