# US 12,183,494 B2 · Method for forming rare earth-substitute nanocomposite

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- Number: US 12,183,494 B2
- Document ID: US12183494B2
- Status: Granted
- Kind: B2
- Application number: 18/791,804
- Filed: 2024-08-01
- Published: 2024-11-28
- Granted: 2024-12-31
- Earliest claimed: 2021-05-07
- Assignees: Imam Abdulrahman Bin Faisal University
- Applicants: Imam Abdulrahman Bin Faisal University
- Inventors: Yassine Slimani; Munirah Abdullah Almessiere; Abdulhadi Baykal
- Web page: https://patentgrep.com/patent/US12183494B2

## CPC

- H01F 1/342: {Oxides (H01F1/36 and H01F1/38 take precedence)}
- H01F 7/06: Electromagnets; Actuators including electromagnets {(electric coils H01F5/00; devices for holding workpieces using electric force B23Q3/15; load-engaging elements for lifting articles electromagnetically B66C1/06; electromagnetic couplings F16D27/00; magnetic brakes F16D63/002; electromagnetically operated valves F16K11/24, F16K31/00; analysing materials by magnetic means G01N27/72, G01N27/80; electromagnets for winding mechanical clocks G04C1/02; electromagnetic relays H01H51/00; windings for salient poles of dynamo-electric machines H02K3/18; electromagnets for telegraphic communication H04L; for arc lamps H05B31/28)}
- B82Y 25/00: Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
- B82Y 40/00: Manufacture or treatment of nanostructures
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES

## Abstract

A magnetoelectric multiferroic nanocomposite. The nanocomposite comprises a ferroelectric perovskite oxide and a rare-earth substituted mixed ternary transition metal ferrite of the formula A1−xBxRyFe2−yO4. The nanocomposite has a high dielectric constant, low dielectric loss, both stable over a wide frequency range. These properties may make the nanocomposite desirable for applications in microelectronic devices, sensors and antennas.

## Claims

### Claim 1

A method of forming a nanocomposite, comprising:
mixing ferroelectric perovskite oxide particles and rare-earth substituted mixed ternary transition metal ferrite particles to form a particle mixture, wherein the mixing includes combining a solution of Thulium oxide with a solution of transition metal nitrate salts to form the perovskite oxide particles and the rare-earth substituted mixed ternary transition metal ferrite particles;
milling the particle mixture to form a precursor powder;
pressing the precursor powder to form a pellet; and
sintering the pellet to form the nanocomposite;
wherein the rare-earth substituted mixed ternary transition metal ferrite particles are of formula
A1−xBxRyFe2−yO4,
wherein A and B represent different transition metals;
0<x<1;
R is Thulium;
0<y<0.2; and
the rare-earth substituted mixed ternary transition metal ferrite particles are superparamagnetic at 0 to 50° C.

### Claim 2 (depends on 1)

The method of claim 1, wherein the ferroelectric perovskite oxide particles are lead-free BaTiO3.

### Claim 3 (depends on 1)

The method of claim 1, wherein the ferroelectric perovskite oxide particles have a mean particle size of less than 1000 nm.

### Claim 4 (depends on 1)

The method of claim 1, wherein A is cobalt.

### Claim 5 (depends on 1)

The method of claim 1, wherein B is zinc.

### Claim 6 (depends on 1)

The method of claim 1, wherein 0.1≤x<0.5.

### Claim 7 (depends on 1)

The method of claim 1, wherein the rare-earth substituted mixed ternary transition metal ferrite particles are substantially free of nickel.

### Claim 8 (depends on 1)

The method of claim 1, wherein R is thulium.

### Claim 9 (depends on 1)

The method of claim 1, wherein 0.001≤y≤0.1.

### Claim 10 (depends on 1)

The method of claim 1, wherein the rare-earth substituted mixed ternary transition metal ferrite particles have a mean particle size of 10 nm to 5 μm.

### Claim 11 (depends on 1)

The method of claim 1, wherein a molar ratio of the rare-earth substituted mixed ternary transition metal ferrite particles to the ferroelectric perovskite oxide particles is 0.05:1 to 0.5:1.

### Claim 12 (depends on 1)

The method of claim 1, wherein the nanocomposite has a dielectric constant (ε′) of 10 to 15 for frequencies of 100 to 106 Hz at 0 to 140° C.

### Claim 13 (depends on 1)

The method of claim 1, wherein the nanocomposite has a dielectric loss tangent of 0 to 0.1 for frequencies of 100 to 106 Hz at 0 to 140° C.

### Claim 14 (depends on 1)

The method of claim 1, wherein the nanocomposite has a band gap of 1.40 to 2.5 eV.

### Claim 15 (depends on 1)

The method of claim 1, wherein the nanocomposite has a saturation magnetization of 0.1 to 20 emu/g at 0 to 50° C. and a magnetic coercivity of 10 to 2000 Oe at 0 to 50° C.

### Claim 16

A method of forming a nanocomposite, comprising:
mixing ferroelectric perovskite oxide particles and rare-earth substituted mixed ternary transition metal ferrite particles to form a particle mixture, wherein the mixing includes combining a solution of a rare earth oxide with a solution of transition metal nitrate salts to form the perovskite oxide particles and the rare-earth substituted mixed ternary transition metal ferrite particles;
milling the particle mixture to form a precursor powder;
pressing the precursor powder to form a pellet; and
sintering the pellet to form the nanocomposite;
wherein the rare-earth substituted mixed ternary transition metal ferrite particles are of formula
A1−xBxRyFe2−yO4,
wherein A and B represent different transition metals:
0<x<1;
R is a rare-earth element;
0<y<0.2; and
the rare-earth substituted mixed ternary transition metal ferrite particles are superparamagnetic at 0 to 50° C.,
wherein the pressing is performed at 900 to 1100 MPa.

### Claim 17 (depends on 1)

The method of claim 1, wherein the sintering is performed at 850 to 1350° C. for 1 to 6 hours.

### Claim 18

A method of forming a nanocomposite, comprising:
mixing ferroelectric perovskite oxide particles and rare-earth substituted mixed ternary transition metal ferrite particles to form a particle mixture, wherein the mixing includes combining a solution of a rare earth oxide with a solution of transition metal nitrate salts to form the perovskite oxide particles and the rare-earth substituted mixed ternary transition metal ferrite particles;
milling the particle mixture to form a precursor powder;
pressing the precursor powder to form a pellet; and
sintering the pellet to form the nanocomposite;
wherein the rare-earth substituted mixed ternary transition metal ferrite particles are of formula
A1−xBxRyFe2−yO4,
wherein A and B represent different transition metals:
0<x<1;
R is a rare-earth element;
0<y<0.2; and
the rare-earth substituted mixed ternary transition metal ferrite particles are superparamagnetic at 0 to 50° C.,
wherein the rare-earth substituted mixed ternary transition metal ferrite particles are prepared by:
mixing a cobalt (II) source, a zinc (II) source, an iron (III) source, and a thulium source in a solvent to form a precursor solution;
adding a base to the precursor solution to form a reaction mixture having a pH of 11 to 12;
ultrasonically treating the reaction mixture at a frequency of 18 to 25 kHz and a power of 50 to 100 W to form a precipitate; and
drying the precipitate to form the rare-earth substituted mixed ternary transition metal ferrite particles.

### Claim 19 (depends on 18)

The method of claim 18, wherein:
the cobalt (II) source is cobalt nitrate;
the zinc (II) source is zinc nitrate;
the iron (III) source is iron nitrate;
the thulium source is thulium oxide;
the base is sodium hydroxide; and
the ultrasonic treatment is performed for 30 to 120 minutes.