A Refrigerator Magnet Analog of Scanning-Probe Microscopy

Lorenz, Julie K.; Olson, Joel A.; Campbell, Dean J.; Lisensky, George C.; Ellis, Arthur B.

doi:10.1021/ed074p1032a

Cited by 9 publications

(10 citation statements)

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“…The effect is most pronounced when the RMs are dragged in a direction perpendicular to their magnetic pole stripes (3)(4)(5).…”

Section: Part B Simulating Probe Microscopy With Rmsmentioning

confidence: 99%

“…8). 3 The composite structure demonstrates both magnetic and polymer properties, and the total fabrication procedure takes about 1.5 h. This experiment was performed by about 500 students in a general chemistry course at the UW-Madison and was well received. great, the impact of the ball will push the magnets apart regardless of the orientation of their magnetic poles.…”

Section: Part C Modeling Extended Ionic and Metallic Bonding Response...mentioning

confidence: 99%

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Chemistry with Refrigerator Magnets: From Modeling of Nanoscale Characterization to Composite Fabrication

Olson¹,

Calderón²,

Doolan³

et al. 1999

J. Chem. Educ.

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Magnets are critical components of an extraordinary range of devices and technologies (1). The basis for many of these applications is the flexible magnet, which is typically a composite material prepared by incorporating magnetic particles into a flexible polymer host. Uses for flexible magnets include auto ignitions, tachometers, magnetic sensors, Hall effect actuators, eddy current devices, synchronous clock and timer motors, bicycle generators, and microwave communication equipment (1). But perhaps the most common place to encounter flexible magnets is on the refrigerator door.The common flexible-sheet refrigerator magnet (RM) has a complex and ingenious magnetic structure maximized for holding power. A sketch of the magnetic fields in a crosssection of an RM is shown in Figure 1A. The field lines in the RM are U-shaped; therefore, the magnetic field is strong on the back side of the magnet and weak on the front side. An RM can be thought of as an array of very small horseshoe magnets (Fig. 1B). The magnetic field structure comprises a striped pattern of alternating north and south poles on the brown, unprinted back side of the RM (Fig. 1C) (2-5), with a typical stripe width of 1-2 mm. This unusual magnetic topography can be used for a number of interesting demonstrations and experiments.Chemically, RMs are composite materials, typically containing magnetic strontium ferrite (SrFe 12 O 19 ) particles dispersed in the elastomer Hypalon. Hypalon is a derivative of polyethylene with some hydrogen atoms replaced by Cl and SO 2 Cl: C X

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“…The effect is most pronounced when the RMs are dragged in a direction perpendicular to their magnetic pole stripes (3)(4)(5).…”

Section: Part B Simulating Probe Microscopy With Rmsmentioning

confidence: 99%

Section: Part C Modeling Extended Ionic and Metallic Bonding Response...mentioning

confidence: 99%

Chemistry with Refrigerator Magnets: From Modeling of Nanoscale Characterization to Composite Fabrication

Olson¹,

Calderón²,

Doolan³

et al. 1999

J. Chem. Educ.

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“…11−15 Of these models, most are scanning probe microscopy (SPM), with a focus on atomic force microscopy. 11,14,15 Despite these exciting precedents, there are few options for modeling electron microscopy. To address this need, we developed an inexpensive macroscale model of a transmission electron microscope (TEM) that produces plan view "micrographs" on cyanotype paper and is capable of a tilt series function.…”

Section: ■ Introductionmentioning

confidence: 99%

A Macroscale Model for Hands-On Activities Demonstrating Transmission Electron Microscopy

et al. 2019

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Although nanotechnology lessons are increasingly integrated into curricula, students still face significant challenges in understanding the characterization techniques used to investigate nanotechnology. Many characterization techniques, such as transmission electron microscopy (TEM), are prohibitively expensive for primarily undergraduate institutions and completely inaccessible for high schools and local outreach programs. When TEMs are accessible, opportunities for hands-on use are still limited due to logistics and costs for instrument time. In this project, we present a low cost ($50 USD) macroscale TEM model that uses cyanotype paper for "imaging" and is constructed of materials available at local hardware and pet supply stores and chemistry stockrooms. This model allows students to investigate properties of TEM micrographs including thickness contrast, diffraction contrast, plan view, and tilt series imaging through a series of four hands-on activities in an active-learning setting. The four activities are identification of mystery objects from student cyanotype "micrographs", sizing objects from their micrographs using a scale bar, sketching the structure of a mystery 3D object from acquired tilt series images, and developing unique micrographs with objects of the students' choice and predicting features of the resulting images. The TEM model and associated activities were tested with groups of STEM (Science, Technology, Engineering and Mathematics)-interested high schoolers and were found to enhance student engagement, enjoyment, and understanding of certain properties of TEM micrographs.

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“…One hands-on activity previously described in this Journal uses a simple refrigerator magnet to mimic atomic force microscopy. 7 The activity described here uses a simple scanning tunneling microscope model, made from readily available components, with a photocell circuit constructed after Gordon et al 8 A CdS photocell placed above plastic model atomic surfaces detects light from a light emitting diode (LED) placed below. (Light corresponds to tunneling current.)…”

mentioning

confidence: 99%