Multilayer iron nitride hard magnetic materials

A method comprising:

• heating an iron source to form a vapor comprising an iron-containing compound;
• depositing iron from the vapor comprising the iron-containing compound and nitrogen from a vapor comprising a nitrogen-containing compound over a substrate to form a first layer comprising iron and nitrogen;
• depositing iron from the vapor comprising the iron-containing compound, nitrogen from the vapor comprising nitrogen-containing compound, and at least one of carbon, boron, or oxygen from a vapor comprising the at least one of carbon, boron, or oxygen over the substrate to form a second layer comprising iron, nitrogen, and the at least one of carbon, boron, or oxygen;
• and
• annealing the first layer to form at least some crystals comprising α″-Fe16N2 and the second layer to form at least some crystals comprising α″-Fe16(NxZ1-x)2 or a mixture of α″-Fe16N2 crystals and α″-Fe16Z2 crystals, wherein Z comprises the at least one of carbon, boron, or oxygen, and wherein x is a number greater than zero and less than one.

A method comprising:

• submerging a substrate in a first coating solution comprising a nitrogen-containing solvent and an iron source, wherein the first coating solution is saturated with the iron source at a first temperature above a liquidus temperature of an iron-nitrogen mixture to be deposited from the first coating solution;
• cooling the first coating solution to a second temperature to form a supersaturated first coating solution, wherein the second temperature is below the liquidus temperature of the iron-nitrogen mixture;
• maintaining the substrate in the supersaturated first coating solution to allow a first layer comprising iron and nitrogen to form over the substrate;
• submerging the substrate in a second coating solution comprising a nitrogen-containing solvent, an iron source, and a compound containing at least one of carbon, boron, or oxygen, wherein the second coating solution is saturated with the iron source at a third temperature above a liquidus temperature of a mixture to be deposited from the second coating solution;
• cooling the second coating solution to a fourth temperature to form a supersaturated second coating solution, wherein the fourth temperature is below the liquidus temperature of the mixture;
• maintaining the substrate in the supersaturated second coating solution to allow a second layer comprising iron, nitrogen, and the at least one of carbon, boron, or oxygen to form over the substrate;
• annealing the first layer to form at least some crystals comprising α″-Fe16N2 and the second layer to form at least some crystals comprising α″-Fe16(NxZ1-x)2 or a mixture of α″-Fe16N2 crystals and α″-Fe16Z2 crystals, wherein Z comprises the at least one of carbon, boron, or oxygen, and wherein x is a number greater than zero and less than one.