Pattern writing of magnetic order using ion irradiation of a magnetic phase transitional thin film

A method comprising:

• providing an article comprising:
• a substrate;
• and a layer of an FeRh alloy disposed on the substrate;
• wherein the alloy comprises:
• a continuous antiferromagnetic phase;
• and one or more discrete phases smaller in area than the continuous phase having a lower metamagnetic transition temperature than the continuous phase;
• wherein the one or more discrete phase has a superparamagnetic limit that exceeds the superparamagnetic limit of the continuous phase;
• wherein the discrete phase is ferromagnetic;
• and
• orienting the magnetic polarization of a first ferromagnetic discrete phase.

A method comprising:

• providing an article comprising:
• a substrate;
• and a layer of an FeRh alloy disposed on the substrate;
• wherein the alloy comprises:
• a continuous antiferromagnetic phase;
• and one or more discrete phases smaller in area than the continuous phase having a lower metamagnetic transition temperature than the continuous phase;
• wherein the one or more discrete phase has a superparamagnetic limit that exceeds the superparamagnetic limit of the continuous phase;
• wherein the discrete phase is ferromagnetic;
• and
• determining the orientation of the magnetic polarization of the ferromagnetic discrete phase.

A method comprising:

• providing an article comprising:
• a substrate;
• and a layer of an FeRh alloy disposed on the substrate;
• wherein the alloy comprises:
• a continuous antiferromagnetic phase;
• and one or more discrete phases smaller in area than the continuous phase having a lower metamagnetic transition temperature than the continuous phase;
• wherein the one or more discrete phase has a superparamagnetic limit that exceeds the superparamagnetic limit of the continuous phase;
• and
• detecting the presence, absence, or location of any ferromagnetic discrete phases.

A method comprising:

• providing an article comprising:
• a substrate;
• and a layer of an FeRh alloy disposed on the substrate;
• wherein the alloy comprises:
• a continuous antiferromagnetic phase;
• and one or more discrete phases smaller in area than the continuous phase having a lower metamagnetic transition temperature than the continuous phase;
• wherein the one or more discrete phase has a superparamagnetic limit that exceeds the superparamagnetic limit of the continuous phase;
• wherein at least two of the discrete phases have different metamagnetic temperatures;
• and
• detecting the presence, absence, or location of any ferromagnetic discrete phases;
• adjusting the temperature of the article;
• and
• detecting the presence, absence or location of any ferromagnetic discrete phases.

A method comprising:

• providing an article comprising:
• a substrate;
• and a layer of an FeRh alloy disposed on the substrate;
• wherein the alloy comprises:
• a continuous antiferromagnetic phase;
• and one or more discrete phases smaller in area than the continuous phase having a lower metamagnetic transition temperature than the continuous phase;
• wherein the one or more discrete phase has a superparamagnetic limit that exceeds the superparamagnetic limit of the continuous phase;
• wherein the substrate comprises a piezoelectric material;
• and
• applying a voltage to the piezoelectric material that alters the metamagnetic temperature of one or more of the discrete phases;
• and detecting the presence, absence, or location of any ferromagnetic discrete phases.

A method comprising:

• providing an article comprising:
• a substrate;
• and
• a layer comprising a continuous phase of an antiferromagnetic FeRh alloy disposed on the substrate;
• and
• directing an ion source at one or more portions of the alloy to create one or more discrete phases smaller in area than the continuous phase having a lower metamagnetic transition temperature than the continuous phase;
• wherein the one or more discrete phases has a superparamagnetic limit that exceeds the superparamagnetic limit of the continuous phase.

A method comprising:

• providing an article comprising:
• a substrate;
• and
• a layer comprising a continuous phase of an antiferromagnetic FeRh alloy disposed on the substrate;
• and
• directing an electron source at one or more portions of the alloy to create one or more discrete phases smaller in area than the continuous phase having a lower metamagnetic transition temperature than the continuous phase;
• wherein the one or more discrete phases has a superparamagnetic limit that exceeds the superparamagnetic limit of the continuous phase.