Magnetoelectric multilayer composites for field conversion

• US 6,835,463 B2
• Filed: 04/18/2002
• Issued: 12/28/2004
• Est. Priority Date: 04/18/2002
• Status: Expired due to Term

• Current Assignee: Oakland University
• Original Assignee: Oakland University
• Inventors: Srinivasan, Gopalan
• Primary Examiner(s): Bernatz, Kevin M.
• Application Number:
  US10/125,670
• Publication Number:
  US 20030197970A1
• Time in Patent Office: 985 Days
• Field of Search: 428/548, 428/611, 428/668, 428/680, 428/693, 428/702, 428/615, 428/681, 428/692, 428/900, 310/311, 324/207.13
• US Class Current: 428/548
• CPC Class Codes: H01F 1/344 Ferrites, e.g. having a cubic spinel structure (X2+O)(Y23+O3), e.g. magnetite Fe3O4
• CPC Class Codes: H01F 41/0246 Manufacturing of magnetic circuits by moulding or by pressing powder magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36
• CPC Class Codes: H10N 30/85 Piezoelectric or electrostrictive active materials
• CPC Class Codes: H10N 35/85 Magnetostrictive active materials
• CPC Class Codes: Y10T 428/1114 having tunnel junction effect
• CPC Class Codes: Y10T 428/1143 with defined structural feature
• CPC Class Codes: Y10T 428/12028 Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, etc.]
• CPC Class Codes: Y10T 428/12465 having magnetic properties, or preformed fiber orientation coordinate with shape
• CPC Class Codes: Y10T 428/12861 Group VIII or IB metal-base component
• CPC Class Codes: Y10T 428/12944 Ni-base component
• CPC Class Codes: Y10T 428/325 Magnetic layer next to second metal compound-containing layer

Abstract

Magnetoelectric multilayer composites comprising alternate layers of a bimetal ferrite wherein one of the metals is zinc and a piezoelectric material for facilitating conversion of an electric field into a magnetic field or vice versa. The preferred composites include cobalt, nickel, or lithium zinc ferrite and PZT films which are arranged in a bilayer or in alternating layers, laminated, and sintered at high temperature. The composites are useful in sensors for detection of magnetic fields; sensors for measuring rotation speed, linear speed, or acceleration; read-heads in storage devices by converting bits in magnetic storage devices to electrical signals; magnetoelectric media for storing information; and high frequency devices for electric field control of magnetic devices or magnetic field control of electric devices.

Claims

1. A sintered magnetoelectric composite comprising:

(a) at least one magnetostrictive composition comprising a layer of a sintered bimetal ferrite powder wherein one of the metals is zinc, and wherein the composite has a magnetoelectric voltage coefficient of at least 100 mV/cm Oe measured at a frequency of 100 Hz at room temperature; and

(b) at least one layer of a piezoelectric composition as a powder joined to the at least one magnetostrictive composition wherein the layers are sintered together.

2. The composite of claim 1 wherein the piezoelectric material is selected from the group consisting of lead zirconate titanate (PZT), lead zincate niobate (PZN), lead zincate niobate lead-titanate (PZN-PT), lead magnesium niobate lead-titanate (PMN-PT), lead lanthanum zirconate titanate (PLZT), Nb/Ta doped-PLZT, and barium zirconate titanate (BZT).

3. The composite of claims 1 or 2 wherein the bimetal ferrite has the formula:

4. The composite of claims 1 or 2 wherein the bimetal ferrite has the formula:

5. The composite of claims 1 or 2 wherein the bimetal ferrite has the formula: