Improvement of the Sensitivity of a High-Frequency Carrier-Type Magnetic Field Sensor Through the Use of an Edge Extension Structure

Improvement of the sensitivity of a high-frequency carrier-type (HFC-type) magnetic field sensor through the use of an edge extension structure is reported. The HFC-type magnetic field sensor is composed of a rectangular CoNbZr thin film with a coplanar-structure Cu thin film as an electrode. The edge extension structure causes reduction of the sensor's demagnetization field effect. A variation in the sensor impedance was obtained as a function of the external magnetic field for edge extension lengths ranging from X= 0 mm to X = 1 mm. The length of the sensor was 1 mm, the thickness was 2 μm, and the widths were 20 and 80 μm. It was demonstrated that the gain of an HFC-type magnetic sensor with an edge extension length of X = 1 mm was three times higher than that of a sensor with an edge extension length of X= 0 mm. This result shows that an edge extension structure improves the sensitivity of an HFC-type magnetic field sensor.