Detection of single magnetic nanobead with a nano-superconducting quantum interference device

Abstract

W e report the use of an ultralow noise nano-superconducting quantum interference device nanoSQUID_ to measure the hysteretic magnetization behavior of a single FePt nanobead at a temperature of around 7 K in a magnetic field of only 10 mT. W e also show that the nanobead can be accurately positioned with respect to the SQUID loop and then removed without affecting SQUID performance. This system is capable of further development with wide applications in nanomagnetism.

Detection of Proteins Using Nano Magnetic Particle Accumulation-Based Signal Amplification

“…After the separation step, there are various techniques to read out signal from magnetic particles; electrochemical detection [10], magnetometer [11], magnetic remanence [12], magnetoresistance [13,14], hall sensors [15], optical methods such as laser diffraction [16], optical light microscope [17], and fluorescent detection [18]. Common approaches to amplifying the signal from magnetic particle-based biosensors are the use of additional magnetic [16] or nonmagnetic particles, such as labels coated with biomolecules to either bind to a target molecule [19] or bind to magnetic beads [18,20].…”

Fabrication and Analogue Applications of NanoSQUIDs Using Dayem Bridge Junctions

“…This could be of significance not only for the IT and telecom communities (where complex spintronics properties may play an essential role in future developments) but also for future medical and biological applications. The burgeoning field of quantum technologies, including quantum information processing is increasingly relying on nanoSQUIDs for interrogation of single spin systems [15]. It was proposed some years ago that, if a small enough SQUID is used, its sensitivity should be sufficient to detect the reversal of a single Bohr magneton moment [16].…”

“…Note, however, that the applied field will also contribute a component to the flux coupled to the SQUID. It is possible to calibrate out this effect as shown elsewhere [15], as the system is measured before and after the particle is attached.…”

Alternating current magnetic susceptibility of a molecular magnet submonolayer directly patterned onto a micro superconducting quantum interference device

“…This method opens the possibility of applying ac susceptibility experiments to characterize two-dimensional arrays of single molecule magnets within a wide range of temperatures and frequencies. The ac magnetic susceptibility of magnetic nanoparticles and single molecule magnets (SMMs) provides useful information on their spin and magnetic anisotropy, 1 as well as on the magnetic relaxation mechanisms.2-4 Miniaturized superconducting quantum interference devices [5][6][7][8][9] (SQUIDs) should eventually become capable 8,10 of measuring the magnetization reversal of a SMM (µ i ∼ 20µ B for the archetypal Mn 12 molecule). However, detecting the linear response sets even more stringent conditions: at T = 1 K, a magnetic field H = 24 A/m (0.3 Oe) induces a magnetic polarization µ ≃ 0.007µ B on the same Mn 12 cluster.…”

“…2-4 Miniaturized superconducting quantum interference devices [5][6][7][8][9] (SQUIDs) should eventually become capable 8,10 of measuring the magnetization reversal of a SMM (µ i ∼ 20µ B for the archetypal Mn 12 molecule). However, detecting the linear response sets even more stringent conditions: at T = 1 K, a magnetic field H = 24 A/m (0.3 Oe) induces a magnetic polarization µ ≃ 0.007µ B on the same Mn 12 cluster.…”