Multiferroic materials

Patent metadata

Field	Value
Publication number	US-2018057409-A1
Application number	US-201615558424-A
Country	US
Kind code	A1
Filing date	Mar 16, 2016
Priority date	Mar 16, 2015
Publication date	Mar 1, 2018
Grant date	—

Abstract

The present invention relates to new multiferroic materials. More particularly, the present invention relates to new multiferroic single phase ceramic materials as well as to thin films formed from these materials, methods of preparing these materials and their use as multiferroic materials in electronic components and devices.

First claim

1 . A single phase ceramic material comprising a morphotropic phase boundary and a continuous percolating network of magnetic cations.

2 . A single phase ceramic material according to claim 1 , wherein the ceramic material comprising a morphotropic phase boundary is ferroelectric and the magnetic cations are present in an amount sufficient to impart ferromagnetic properties to the material.

3 . A single phase material according to claim 1 , wherein the material is multiferroic at a temperature between 243K and 473K.

4 . A single phase material according to claim 1 , wherein the material is multiferroic at a temperature between 273K and 370K.

5 . A single phase ceramic material according to claim 1 , wherein the material has the composition shown in formula (I) below:
(1- x )LM a (1-y)/2 Fe y Mg (1-y)/2 O 3 - x Q  (I)
wherein:
x is a value ranging from 0.01 to 0.4;
y is a value ranging from 0.01 to 0.9;
L is selected from Bi, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or Y;
M a is selected from Ti, Hf or Zr; and
Q is:
a) a group of formula:
RM b O 3
wherein:
R is selected from Ca, Sr or Ba; and
M b is selected from Ti or Hf or Zr; or

b) a group selected from one or more of the following: [BiM d O 3 ] q [Bi(M e ) r (M f ) (1-r) O 3 ] (1-q) , CaZrO 3 , SrZrO 3 , BaZrO 3 , KNbO 3 , NaNbO 3 , Ca 2 FeNbO 6 , PbZr 1-p Ti p O 3 , LnScO 3 , LnGaO 3 or Ln 2 TiM c O 6 ;
wherein:
Ln is selected from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or Y;
p is a value ranging from 0 to 1;
q is a value ranging from 0 to 1;
r is a value ranging from 0 to 1;
M c is selected from Mg, Ni, Cu, Mn, Co, Fe or Zn;
M d is selected from Fe, Mn, or Cr; and
M e and M f are independently selected from one or more of the following Zn, Ti, Sn, Mg, Nb, Ta, W, Li, Ni, Cu, Fe, Cr or Mn.

6 . A single phase ceramic material according to claim 5 , wherein said material has the structure (Ia) shown below:
(1- x )BiM a (1-y)/2 Fe y Mg (1-y)/2 O 3 - x RM b O 3   (Ia)
wherein:
x is between 0.01 and 0.4;
y is between 0.01 and 0.9;
R is selected from Ca or Sr; and
M a and M b are each independently selected from Zr or Ti.

7 . A single phase ceramic material according to claim 5 , wherein M a is Ti.

8 . A single phase material ceramic material according to claim 5 , wherein M b is Ti.

9 . A single phase ceramic material according to claim 5 , wherein R is Ca.

10 . A single phase ceramic material according to claim 5 , wherein x is between 0.05 and 0.20.

11 . A single phase ceramic material according to claim 5 , wherein x is 0.15.

12 . A single phase ceramic material according to claim 5 , wherein y is between 0.6 and 0.9.

13 . A single phase ceramic material according to claim 5 , wherein y is between 0.75 and 0.85.

14 . A single phase ceramic material according to claim 5 , wherein the single phase ceramic material is multiferroic at a temperature between 243K and 473K.

15 . A single phase ceramic material according to claim 5 , wherein the single phase ceramic material is multiferroic at a temperature between 293K and 370K.

16 . A single phase ceramic material comprising:
(i) a single phase ceramic material of formula I, wherein the material has the composition shown below:
(1- x )LM a (1-y)/2 Fe y Mg (1-y)/2 O 3 - x Q  (I)

wherein:
x is a value ranging from 0.01 to 0.4;
y is a value ranging from 0.01 to 0.9;
L is selected from Bi, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or Y;
M a is selected from Ti, Hf or Zr; and
Q is:
a) a group of formula:
RM b O 3
wherein:
R is selected from Ca, Sr or Ba; and
M b is selected from Ti, Hf or Zr; or

b) a group selected from one or more of the following: [BiM d O 3 ] q [Bi(M e ) r (M f ) (1-r) O 3 ] (1-q) , CaZrO 3 , SrZrO 3 , BaZrO 3 , KNbO 3 , NaNbO 3 , Ca 2 FeNbO 6 , PbZr 1-p Ti p O 3 , LnScO 3 , LnGaO 3 or Ln 2 TiM c O 6 ;
wherein:
Ln is selected from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or Y;
p is a value ranging from 0 to 1;
q is a value ranging from 0 to 1;
r is a value ranging from 0 to 1;
M c is selected from Mg, Ni, Cu, Mn, Co, Fe or Zn;
M d is selected from Fe, Mn, or Cr; and
M e and M f are independently selected from one or more of the following Zn, Ti, Sn, Mg, Nb, Ta, W, Li, Ni, Cu, Fe, Cr or Mn; and

(ii) a further material, optionally selected from one or more of the following:
BiTi 3/8 Fe 2/8 Ni 3/8 O 3 ,BiM d O 3 ,BiM e M f O 3 ,CaZrO 3 ,SrZrO 3 ,BaZrO 3 ,KNbO 3 ,NaNbO 3 ,Ca 2 FeNbO 6 ,LnScO 3 ,LnGaO 3 or LnTiM c O 6 ;
wherein
Ln is selected from La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu or Y;
p is a value ranging from 0 to 1;
M c is selected from Mg, Ni, Cu or Zn;
M d is selected from Fe, Mn, or Cr; and
M e and M f are independently selected from one or more of the following Zn, Ti, Sn, Mg, Nb, Ta, W, Li, Ni, Cu, Fe, Cr or Mn.

17 . A process for the preparation of a single phase ceramic material, wherein the single phase ceramic material comprises a morphotropic phase boundary and a continuous percolating network of magnetic cations, said process comprising sintering a material capable of forming a single phase ceramic material comprising a morphotropic phase boundary in the presence of a material capable of forming a continuous percolating network of magnetic cations within the morphotropic phase boundary of the ceramic material.

18 . A process for forming a single phase ceramic material according to claim 16 , comprising:
combining and milling materials of the formulae A to E shown below:
L 2 O 3   Formula A

RCO 3   Formula B

Fe 2 O 3   Formula C

MaO 2   Formula D

M b O 2   Formula E

wherein L, R, M a and M b are as defined in claim 5 ; with a material of the formula F:
MgCO 3 .Mg(OH) 2 .z H 2 O  Formula F

wherein z is an integer between 0-5;
in the presence of a suitable organic solvent;
(ii) evaporating the organic solvent and pressing the resulting powder to form a pellet; (iii) calcinating the pellet one or more times; and (iv) optionally sintering the powder in the presence of a binder and MnO 2 .

19 . A process according to claim 18 , wherein the organic solvent in step (i) is ethanol.

20 . A process according to claim 18 , wherein the calcination of step (iii) is conducted at a temperature between 1190K and 1250K.

21 . A process according to claim 18 , wherein the binder of step (iv) is polyvinyl butyral.

22 . A thin film formed from a single phase ceramic material according to claim 1 .

23 . A process of forming a thin film according to claim 22 , the process comprising depositing a thin film of a single phase ceramic material on to a substrate.

24 . A process of forming a thin film according to claim 23 , wherein the process of depositing the thin film is selected from pulsed layer deposition (PLD), atomic layer deposition (ALD), chemical vapour deposition (CVD) or physical vapour deposition (PVD).

25 . An electronic component comprising a single phase ceramic material according to claim 1 .

26 . An electronic component according to claim 25 , wherein the electronic component is selected from a memory device, a tunnel junction, a magnetic field sensor, a transmitter, a receiver, a transmitter-receiver module, a phase array system or a resonator.

Assignees

• Univ Liverpool

Inventors

• Rosseinsky Matthew J
• Mandal Pranab
• Alaria Jonathan
• Claridge John
• Pitcher Michael

Classifications

• C04B2235/85

  Intergranular or grain boundary phases · CPC title

• C04B2235/656

  characterised by specific heating conditions during heat treatment · CPC title

• C04B2235/3298

  Bismuth oxides, bismuthates or oxide forming salts thereof, e.g. zinc bismuthate · CPC title

• C04B2235/3274

  Ferrites · CPC title

• C04B2235/3236

  Alkaline earth titanates · CPC title