JP2002005891A - Magnetic field applying apparatus of squid microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the magnitude of a magnetic field being applied controllable such that a uniform magnetic field can be applied to an object to be measured over the entire measuring range thereof in a scanning SQUID microscope having an SQUID as a magnetic sensor. SOLUTION: In the SQUID microscope, a table 1 for placing a sample 5 being measured and scanning stage 2 for moving the sample table 1 in XYZ direction, a first SQUID sensor 4 disposed oppositely to the sample 5, a magnetic field applying coil 7 disposed to apply a magnetic field to the sample 5, and a second SQUID sensor 6 disposed farther from the sample 5 that the first SQUID sensor 4, are set. The magnitude of the magnetic field being applied is controlled by the output from the second SQUID sensor 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning type small magnetic field measuring apparatus, which is applied to the evaluation of superconducting materials, magnetic materials, and processed products or functional devices using them.
It relates to a UID microscope.

[0002]

2. Description of the Related Art FIG. 2 shows a configuration diagram of a conventional SQUID microscope. The SQUID microscope includes a sample setting table 1 on which a measurement sample 5 is set, a scanning stage 2 for moving the sample setting table 1 to XYZ, and a SQUID sensor cooled by a cooling device 3 and set to oppose the measurement sample 5. 4.
The scanning stage adjusts the position in the Z-axis direction, the SQUID sensor 4 is brought close to the measurement sample 5, the measurement sample 5 is scanned in the XY plane by the scanning stage, and the magnetic field distribution on the measurement sample 5 generated by the measurement sample 5 is determined. Measure.

[0003]

In order to perform measurement while applying a magnetic field, it is necessary to generate a uniform magnetic field over the entire scanning range. For this purpose, a Helmholtz coil is considered, but a large coil is required. Therefore, there has been a problem that measurement is conventionally performed without applying a magnetic field.

[0004]

In order to solve the above-mentioned problems, according to the present invention, an SQ for detecting only an applied magnetic field is provided.
By providing a UID sensor separately from the SQUID sensor for detection and controlling the magnitude of the applied magnetic field, a small magnetic field applying coil can be used to generate a uniform magnetic field over the entire scanning range. Thus, measurement was possible while applying a magnetic field using a SQUID microscope.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment corresponding to the first aspect of the present invention will be described below. FIG. 1 shows an overall configuration diagram of a measuring device according to a first embodiment of the present invention. The SQUID microscope according to the present invention includes a sample setting table 1 on which a measurement sample 5 is set.
And scanning stage 2 for moving this sample mounting table 1 to XYZ
And the first SQUI installed to oppose measurement sample 5
A D sensor 4, a magnetic field application coil 7 installed to apply a magnetic field to the measurement sample 5, and a first
The second SQU installed at a position farther than the SQUID sensor 4
An ID sensor 6, a power supply 8 for controlling the current flowing through the magnetic field applying coil using the output of the second SQUID sensor 6 as a control signal, and a cooling device for cooling the first SQUID sensor 4 and the second SQUID sensor 3.

In such a configuration, the Z-axis is driven by the scanning stage 2 and the first SQUID sensor 4
Closer. Next, while measuring the magnetic field to be applied to the measurement sample 5 with the second SQUID sensor 6, the magnetic field applying power source 8
Is adjusted, and a current for generating a magnetic field is caused to flow through the magnetic field application coil 7.
Then, the XY axes are driven by the scanning stage 2, and the magnetic field distribution of the measurement sample 5 is measured while scanning the measurement range of the measurement sample 5 with the first SQUID sensor 4. The first SKU
The magnetic field distribution of the measurement sample 5 is measured by the ID sensor 4, and the magnetic field generated by the magnetic field application coil 7 is constantly measured by the second SQUID sensor 6. Then, the output signal of the second SQUID sensor 6 is fed back to the magnetic field application power supply 8 so that the magnetic field measured by the second SQUID sensor 6 is always constant, and the current flowing through the magnetic field application coil 7 is controlled. Control.

[0007]

According to the present invention, a uniform magnetic field can be generated over the entire scanning range, and the physical properties of a measurement sample such as a superconducting material or a magnetic material in a magnetic field can be evaluated by SQ.
There is an effect that it can be performed by a UID microscope.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a measuring device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a measuring device according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sample mounting table 2 XYZ scanning stage 3 Cooling device 4 First SQUID sensor 5 Measurement sample 6 Second SQUID sensor 7 Magnetic field application coil 8 Power supply for magnetic field application

Claims (1)

[Claims] 1. A sample mounting table for mounting a measurement sample, a scanning stage, a first SQUID sensor, a magnetic field application coil installed so as to apply a magnetic field to the measurement target, and a second SQUID sensor. A control device that controls a magnetic field generated by the magnetic field applying coil according to an output of the second SQUID sensor, and a cooling device that cools the first SQUID sensor and the second SQUID sensor. Magnetic field applying device for SQUID microscope.