Provided are a magnetic marker and a magnetic marker detection system with a reduced magnetic force. The magnetic marker detection system (1S) in which magnetism generated from the magnetic marker (1) laid on a road surface (53) is detected by a magnetic sensor (2) attached to a vehicle's body floor (50) of a vehicle (5) is a system with the magnetic marker (1) and the magnetic sensor (2) in combination, the magnetic marker having a magnetism reach ratio Gh/Gs, which is a ratio of a magnetic flux density Gh at a position at a height of 250 mm with respect to a magnetic flux density Gs of a surface, being equal to or larger than 0.5% and the magnetic sensor using a magneto-impedance element including a magneto-sensitive body with impedance changing in accordance with an external magnetic field.

A current sensor includes a conductor through which current to be measured flows and which has dimensions in a length direction, a width direction, and a height direction, and first and second magnetic sensors that detect the strength of a magnetic field generated by the current. Each of the first and second magnetic sensors is positioned in an area between first and second conductor portions in the width direction and an area extending from one end to the other end in the height direction of the first and second conductor portions.

A current measurement circuit for determining a start time t.sub.START, an end time t.sub.END, and/or a peak time t.sub.MAX for a current pulse passing through a current conductor. The current measurement circuit includes a pickup coil and a threshold crossing detector. The pickup coil generates a voltage V.sub.SENSE proportional to a magnetic field around the conductor, which is proportional to a change in current over time. The threshold crossing detector compares V.sub.SENSE and a threshold voltage and generates an output signal indicative of a transition time and whether a slope of V.sub.SENSE is positive or negative. The current measurement circuit can also include an integrator and a sample and hold circuit. The integrator integrates V.sub.SENSE over time and generates an integrated signal V.sub.SENSE. The sample and hold circuit compares V.sub.SENSE to t.sub.MAX and generates a second output signal which can be used to measure the pulse current.

A magnetic sensor includes: a substrate; and a sensitive portion disposed on the substrate and having a longitudinal direction and a transverse direction. The sensitive portion senses a magnetic field by a magnetic impedance effect. The sensitive portion includes a soft magnetic material layer composed of a soft magnetic material having uniaxial magnetic anisotropy in a direction intersecting the longitudinal direction and sensing the magnetic field. The sensitive portion also includes a secondary soft magnetic material layer laminated between the substrate and the soft magnetic material layer. The secondary soft magnetic material layer is composed of a soft magnetic material with large saturation magnetization compared to the soft magnetic material constituting the soft magnetic material layer.

Disclosed herein is an inductance element for a magnetic sensor. The inductance element includes a first core comprising a first soft magnetic material and having first and second connecting surfaces, a second core comprising a second soft magnetic material different from the first soft magnetic material and having third and fourth connecting surfaces facing the first and second connecting surfaces, respectively, and a coil wound around the first core between the first and second connecting surfaces, wherein the first core is larger in magnetic field strength at which magnetic saturation occurs than the second core, and wherein the second core is higher in permeability than the first core and has at least partially a meander shape.

An electrical pulse current is supplied to an amorphous wire from a pulse generator, an alternate current voltage whose magnitude is in response to an external magnetic field induced at both ends of a detecting coil wound around the amorphous wire is generated, a positive direct current is applied from a positive power supply by superimposing to the amorphous wire as a bias current so as to produce a bias of magnetization within the amorphous wire and the occurrence of pulse noises is restrained, so as to make it possible to perform high-sensitivity magnetic field detection.

A method of manufacturing a magnetic sensor (1) which method includes: forming a hard magnetic material layer (103) to be processed to a thin film magnet (20) on a disk-shaped nonmagnetic substrate (10); forming a soft magnetic material layer (105) laminated on the hard magnetic material layer (103) on the substrate (10), the soft magnetic material layer (105) being processed into a sensitive element sensing a magnetic field; and magnetizing the hard magnetic material layer (103) in the circumferential direction of the disk-shaped substrate 10. Also disclosed is a magnetic sensor assembly.

A magnetic sensor 1 includes: a thin film magnet 20 which is constituted by a hard magnetic material layer 103 and has magnetic anisotropy in an in-plane direction; and a sensitive part 30 including a sensitive element 31 sensing a magnetic field by a magnetic impedance effect, the sensitive element 31 being constituted by a soft magnetic material layer 105 laminated on the hard magnetic material layer 103, having a longitudinal direction and a short direction, and having uniaxial magnetic anisotropy in a direction intersecting the longitudinal direction, in which the longitudinal direction faces in the direction of a magnetic field generated by the thin film magnet 20. The thin film magnet 20 and the sensitive element 31 are provided to constitute a magnetic circuit with a facing member provided outside to face one of magnetic poles of the thin film magnet 20.

A magneto-impedance sensor which makes it possible to further improve the accuracy of external magnetic field measurement includes a magneto-impedance element, a detection circuit, a magneto-sensitive body wiring line and a conductive layer wiring line. The magneto-impedance element includes a magneto-sensitive body and a conductive layer adjacent to the magneto-sensitive body. The magneto-sensitive body and the conductive layer pass a current therethrough in the opposite directions. The magneto-sensitive body wiring line and the conductive layer wiring line are electrically connected to the magneto-sensitive body and the conductive layer, respectively. A detection coil and a detection circuit of the magneto-impedance element are electrically connected to each other through detecting conductive wires. At least parts of these lines are adjacent to each other and allow a current to pass therethrough in opposite directions.

A magnetic detection apparatus according to the present disclosure includes a magnetic sensor and a measurement apparatus. The magnetic sensor includes a first transmission line and a second transmission line arranged to be non-parallel to each other. The measurement apparatus includes a signal generator configured to generate a first incident wave and a second incident wave, a signal detector configured to detect a first reflected wave caused by an impedance mismatch of the first transmission line and a second reflected wave caused by an impedance mismatch of the second transmission line, and a controller. The controller calculates a first magnetic field based on the first incident wave and the first reflected wave and a second magnetic field based on the second incident wave and the second reflected wave and calculates a biaxial magnetic field based on the first magnetic field and the second magnetic field.